Physiology
Songwei Lin; Liquan Shen; Haoxiang Gao; Jiayi Wu; Qingxin Lv; Xin Zhou; Junsheng Li; Xiuxiang Meng
Volume 14, Issue 11 , November 2023, , Pages 589-594
Abstract
Activity patterns and time budgets play a crucial role in the successful farming and management of animals. In this study, the behavior patterns of 53 forest musk deer (Moschus berezovskii) were analyzed from October 2nd to 16th, 2021, throughout the day and night. The results showed a distinct dawn–dusk ...
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Activity patterns and time budgets play a crucial role in the successful farming and management of animals. In this study, the behavior patterns of 53 forest musk deer (Moschus berezovskii) were analyzed from October 2nd to 16th, 2021, throughout the day and night. The results showed a distinct dawn–dusk activity rhythm in the captive forest musk deer with a peak activity observed at dawn (07:00 - 10:00) and dusk (16:00 - 19:00). Additionally, there were smaller activity peaks lasting less than an hour during the nighttime (00:00 - 04:00). Comparing behavior ratios between peak and off-peak periods, it was evident that all behaviors, except rumination (RU), showed significant differences. Furthermore, no significant differences were found in the behavior ratios of the forest musk deer between the daytime and night-time. During the daytime, the percentages of time spent performing locomotion (32.87 ± 3.38%), feeding (14.43 ± 1.81%), and RU (5.62 ± 1.46%) were slightly higher compared to the night-time. Based on these findings, it is important to match the management strategies for musk deer farming with the animals' activity patterns and behavioral rhythms. Doing so can enhance farming outputs and contribute to the welfare of captive forest musk deer.
Physiology
Fereshteh Anbarian; Esmaeal Tamaddonfard; Amir Erfanparast; Farhad Soltanalinejad-Taghiabad
Volume 14, Issue 10 , October 2023, , Pages 549-557
Abstract
The cerebellum and its deep nuclei contribute to the regulation of important functions including motor coordination and pain. Histamine modulates some functions of the fastigial nucleus (FN) such as motor coordination. In this study, by application of histamine and activation of its H1 and H2 receptors, ...
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The cerebellum and its deep nuclei contribute to the regulation of important functions including motor coordination and pain. Histamine modulates some functions of the fastigial nucleus (FN) such as motor coordination. In this study, by application of histamine and activation of its H1 and H2 receptors, the FN processing of visceral pain, general locomotor activity and motor coordination were targeted. The possible mechanism of action was followed by the inhibition of opioid receptors. The right and left sides of the FN were surgically implanted with guide cannulas. Immediately after an intraperitoneal injection of acetic acid (1.00 mL, 1.00%), the first writhing onset latency and the writhing number over 60 min were recorded. Open-field and rotarod tests were applied for general locomotor and motor coordination assessment, respectively. Histamine and dimaprit (H2 receptor agonist) increased first writhing onset latency, decreased the writhing number and increased falling time from the rod. These effects were prevented by ranitidine (H2 receptor antagonist) pre-treatment. Significant alterations were not observed by histamine H1 receptor agonist (2-pyridylethylamine) and antagonist (mepyramine). Naloxone, with no effect on falling time from the rod, inhibited the antinociceptive effects of histamine and dimaprit. Beam break number was not affected by the above-mentioned treatments. Based on the results, it can be suggested that histamine H2, but not H1 receptors at the FN might have had an inhibitory role on acetic acid-induced visceral pain and improved motor coordination. The antinociception, but not motor coordination might be mediated by FN opioid receptors.
Physiology
Arthénice Jemima Nounamo Guiekep; Augustave Kenfack; Ferdinand Ngoula; Bertin Narcisse Vemo; Kenmeuhe Sidje Nguemmeugne; Etienne Pamo Tedonkeng
Volume 10, Issue 3 , September 2019, , Pages 187-192
Abstract
Acetamiprid (ACP) belonging to the neonicotinoid family used against wide array of pests in agriculture and domestic purposes. In this study, we evaluated the attenuating effects of ethanolic extract of Mangifera indica leaves (EEMI) in averting reproductive toxicity caused by ACP in male guinea pigs. ...
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Acetamiprid (ACP) belonging to the neonicotinoid family used against wide array of pests in agriculture and domestic purposes. In this study, we evaluated the attenuating effects of ethanolic extract of Mangifera indica leaves (EEMI) in averting reproductive toxicity caused by ACP in male guinea pigs. Thirty male guinea pigs were randomly assigned to five treatment groups (n = 6). Group 1 (T0) received distilled water orally; group 2 (T0-) was given 80 mg kg-1 of ACP and groups 3, 4 and 5 were treated, respectively, with EEMI at doses of 50, 100 and 200 mg kg-1 plus ACP. After 90 days, the reaction time, sexual organ weights, sperm count, motility and anomalies, spermatozoa with entire plasma membrane, testicular histology, serum testosterone concentration, testicular malondialdehyde (MDA) level, reduced glutathione (GSH) concentration, testicular superoxide dismutase (SOD) and catalase (CAT) activities were assessed. Co-administration of EEMI significantly reduced the reaction time, sperm anomalies and testicular MDA, SOD and CAT levels compared to the T0- group. Co-treatment of EEMI significantly alleviated sperm count and motility, percentage of spermatozoa with the normal plasma membrane, serum testosterone concentration, accessory sex gland weights, and testicular GSH concentrations. The ACP treatment induced cell membrane degradation in the testis and this effect was prevented with the addition of EEMI. In conclusion, ACP negatively affected the animal reproductive function and induced oxidative stress. The addition of EEMI alleviated the toxic effects of ACP on the reproductive function of male guinea pigs.
Physiology
Azam Abareshi; Akbar Anaeigoudari; Fatemeh Norouzi; Narges Marefati; Farimah Beheshti; Mohsen Saeedjalali; Mahmoud Hosseini
Volume 10, Issue 3 , September 2019, , Pages 199-205
Abstract
Neuro-immune mediators play an important role in the development of sickness behaviors. In the present study, the effect of captopril on sickness behaviors caused by lipopolysaccharide (LPS) was studied in the rats. The animals were randomized into the following groups: control, sham, 10 mg kg-1 captopril ...
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Neuro-immune mediators play an important role in the development of sickness behaviors. In the present study, the effect of captopril on sickness behaviors caused by lipopolysaccharide (LPS) was studied in the rats. The animals were randomized into the following groups: control, sham, 10 mg kg-1 captopril - LPS (Capto 10-LPS), 50 mg kg-1 captopril - LPS (Capto 50-LPS), and 100 mg kg-1 captopril - LPS (Capto 100-LPS). Behavioral tests including open-field (OF), elevated plus maze (EPM) and forced swimming (FS) test were performed, and the serum level of interleukin-6 (IL-6) was assessed. In OF, the number of crossings in the central zone in Capto 10-LPS, Capto 50-LPS, and Capto 100-LPS groups was higher than that of the sham group. In EPM, the open arm entry numbers in the sham group were lower compared to the control group. Furthermore, pretreatment by captopril increased the entries to the open arms. In FS test, the immobility time of the sham group was longer than that of the control group. In Capto 10-LPS, Capto 50-LPS, and Capto 100-LPS groups, immobility was shorter compared to the sham group. In addition, the IL-6 level was higher in the sham group compared to the control group, and treatment with 50 and 100 mg kg-1 of captopril restored the IL-6 level in comparison with the sham group. Results confirmed that pretreatment with captopril ameliorated LPS-caused sickness behaviors and attenuated IL-6 as an inflammatory marker in the rats.
Physiology
Leila Zarei; saied Mahdavi Rad; Amin Abollahzade Fard
Volume 10, Issue 2 , June 2019, , Pages 133-138
Abstract
Obesity causes many problems such as cardiovascular and chronic kidney diseases. The aim of this study was to evaluate the efficacy of retinoic acid and atorvastatin co-administration in kidneys protection against high-fat diet induced damage. Twenty-five male Wistar rats (200.00 ± 20.00 g) were ...
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Obesity causes many problems such as cardiovascular and chronic kidney diseases. The aim of this study was to evaluate the efficacy of retinoic acid and atorvastatin co-administration in kidneys protection against high-fat diet induced damage. Twenty-five male Wistar rats (200.00 ± 20.00 g) were divided into five groups: 1) Control (standard diet), 2) High-fat diet (cholesterol 1.00%, 75 days), 3) High-fat diet + atorvastatin (20.00 mg kg-1 per day, orally, on the 30th day, for 45 consecutive days), 4) High-fat diet + retinoic acid (5 mg kg-1per day, orally, on the 30th day, for 45 consecutive days), and 5) High fat diet + atorvastatin and retinoic acid. At the end, blood and tissue samples were collected for biochemical and histological analyses. The results showed that atorvastatin and retinoic acid alone and in combination decreased cholesterol and low-density lipoprotein and increased high-density lipoprotein in high-fat diet. Also, atorvastatin – caused total antioxidant capacity increase and protein carbonyl content decrease the in the renal tissue. Atorvastatin also prevented high-fat diet-induced renal histological injury. Treatment with atorvastatin significantly mitigates high-fat diet-induced renal changes probably due to its potent antioxidant and lipid-lowering effects. The effect of retinoic acid in renal protection in a high-fat diet is far less than that of atorvastatin. The protective effect of the combination of these two agents in the high-fat diet on the kidneys seems to be due to the effect of atorvastatin.
Physiology
Esmaeal Tamaddonfard; Sina Tamaddonfard; Siamak Cheraghiyan
Volume 9, Issue 4 , December 2018, , Pages 329-335
Abstract
Vitamin B12 modulates pain at the local and peripheral levels. This study has investigated the effects of intracerebroventricular (ICV) injection of vitamin B12 on themuscle pain. We used diclofenac (cyclooxygenase inhibitor) and naloxone (opioid receptors antagonist) to clarify the possible mechanisms. ...
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Vitamin B12 modulates pain at the local and peripheral levels. This study has investigated the effects of intracerebroventricular (ICV) injection of vitamin B12 on themuscle pain. We used diclofenac (cyclooxygenase inhibitor) and naloxone (opioid receptors antagonist) to clarify the possible mechanisms. For ICV injections, a guide cannula was implanted in the left lateral ventricle of the brain. Muscle pain was induced by intramuscular injection of formalin (2.50%; 50 µl) in the right gastrocnemius muscle and the number of paw flinching was recorded at 5-min blocks for 60 min. Locomotor activity was performed using an open-field test. Formalin induced a biphasic pain. Vitamin B12 (1.25, 2.50, 5.00 and 10.00 µg per rat) and diclofenac (12.50 and 25.00 µg per rat) significantly reduced both phases pain intensity. Significant antinociceptive effects were observed after combined treatments of diclofenac (6.25 and 12.50 µg per rat) with vitamin B12 (0.63 and 2.50 µg per rat), respectively. Prior ICV injection of naloxone (10.00 µg per rat) prevented vitamin B12 (10.00 µg per rat) and diclofenac (25.00 µg per rat) induced antinociceptive effects. All the above-mentioned chemicals did not alter locomotor behavior in an open-field test. The present results showed that the cyclooxygenase pathway and opioid receptors may be involved in the central antinociceptive effect of vitamin B12. In addition, opioid receptors might be involved in diclofenac-induced antinociception.
Stem Cells
Vahid Akbarinejad; Parviz Tajik; Mansoureh Movahedin; Reza Youssefi
Volume 8, Issue 1 , March 2017, , Pages 7-13
Abstract
Testosterone is believed to play a significant role in spermatogenesis, but its contribution to the process of spermatogenesis is not completely understood. Given that extracellular matrix (ECM) facilitates differentiation of spermatogonial stem cells (SSCs) during culture, the present study was conducted ...
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Testosterone is believed to play a significant role in spermatogenesis, but its contribution to the process of spermatogenesis is not completely understood. Given that extracellular matrix (ECM) facilitates differentiation of spermatogonial stem cells (SSCs) during culture, the present study was conducted to elucidate whether testosterone contribute to the permissive effect of ECM on SSCs differentiation. In experiment 1, testosterone production was measured in testicular cells cultured for 12 days on ECM or plastic (control). In experiment 2, testosterone production was assessed in testicular cells cultured on ECM or plastic (control) and exposed to different concentrations of hCG. In experiment 3, the gene expression of factors involved in testosterone production was analyzed. Testosterone concentration was lower in ECM than in the control group in experiment 1 (p < 0.05). In experiment 2, testosterone concentration was increased in response to hCG in both groups but cells cultured on ECM were more responsive to hCG than those cultured on plastic (p < 0.05). In the experiment 3, qRT-PCR revealed the inhibitory effect of ECM on the gene expression of steroidogenic acute regulatory protein (StAR) (p < 0.05). Nevertheless, the expression of LH receptor was greater in ECM-exposed than in unexposed cells (p < 0.05). In conclusion, the present study showed that inhibiting the expression of StAR, ECM could lower testosterone production by Leydig cells during in vitro culture. In addition, the results indicated that ECM could augment the responsiveness of Leydig cells to hCG through stimulating the expression of LH receptor.
Physiology
Esmaeal Tamaddonfard; Amir Erfanparast
Volume 8, Issue 1 , March 2017, , Pages 29-34
Abstract
The parafascicular nucleus (PFN) of thalamus, as a supraspinal structure, has an important role in processing of nociceptive information. In addition, μ-opioid receptor contributes to supraspinal modulation of nociception. In the present study, the effects of microinjection of naloxone (a non-specific ...
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The parafascicular nucleus (PFN) of thalamus, as a supraspinal structure, has an important role in processing of nociceptive information. In addition, μ-opioid receptor contributes to supraspinal modulation of nociception. In the present study, the effects of microinjection of naloxone (a non-specific opioid-receptor antagonist) and naloxonazine (a specific μ-opioid receptor antagonist) were investigated on morphine-induced antinociception in a rat model of acute trigeminal pain. Right and left sides of PFN of thalamus were implanted with two guide cannulas. Acute trigeminal pain was induced by local corneal surface application of hypertonic saline and the number of eye wipes as a pain index was recorded for 30 sec. Microinjection of morphine at doses of 1, 2 and 4 μg per site significantly (p < 0.05) decreased the number of eye wipes. Alone microinjection of naloxone (4 μg per site) and naloxonazine (1 and 2 μg per site) significantly (p < 0.05) increased corneal pain severity. Prior microinjection of naloxone (2 and 4 μg per site) and naloxonazine (1 and 2 μg per site) significantly (p < 0.05) prevented the antinociceptive effect induced by morphine (4 μg per site). All the above-mentioned chemicals did not alter locomotor behavior in an open-field test. The results of the present study showed an antinociceptive effect of morphine at the PFN level of thalamus. Mu-opioid receptor of the PFN of thalamus may be involved in morphine-induced antinociception.
Clinical Pathology
Parisa Cheraghi; Seyyed Ali Mard; Tahereh Nagi
Volume 7, Issue 4 , December 2016, , Pages 323-328
Abstract
Hydrogen sulfide (H2S) has been shown to protect the gastric mucosa through several protective mechanisms but till now its effect on mRNA expression of sodium bicarbonate cotransporter 1 (NBC1), trefoil factor1 (TFF1) and trefoil factor2 (TFF2) was not investigated. This study was aimed to evaluate the ...
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Hydrogen sulfide (H2S) has been shown to protect the gastric mucosa through several protective mechanisms but till now its effect on mRNA expression of sodium bicarbonate cotransporter 1 (NBC1), trefoil factor1 (TFF1) and trefoil factor2 (TFF2) was not investigated. This study was aimed to evaluate the effect of H2S on mRNA expression of NBC1, TFF1 and TFF2 in rat gastric mucosa in response to gastric distention. Thirty two rats were randomly assigned into four equal groups. They were control (C), distention (D), propargylglycine (PAG)-, and NaHS-treated groups. To evaluate the effect of exogenous and endogenous H2S on gene expression of NBC1, TFF1 and TFF2, two groups of rats were received H2S donor, intra-peritoneal NaHS (80 µg Kg-1), and PAG (50 mg kg-1), accompanied to stimulate the gastric acid secretion, respectively. Under general anesthesia and laparotomy, a catheter was inserted into the stomach through duodenum for instillation of isotonic saline for gastric distention. Ninety min after beginning the experiment, animals were sacrificed and the gastric mucosa was collected to determine total acid content of gastric effluents and to quantify the mRNA expression of studied genes by quantitative real-time polymerase chain reaction (qRT-PCR). Results showed that A) gastric distention increased the level of mRNA expressions of NBC1, TFF1 and TFF2; B) these levels in NaHS-treated rats were significantly higher than those in Distention group; and C) PAG decreased the expression levels of NBC1 and TFF1. The Findings showed H2S upregulated gene expression of NBC1, TFF1 and TFF2 in gastric mucosa.
Clinical Pathology
Behrokh Marzban Abbasabadi; Mina Tadjalli
Volume 7, Issue 4 , December 2016, , Pages 347-351
Abstract
This study was conducted to evaluate the effect of soy milk on serum 17- β estradiol level and number of neurons in cerebral cortex and hippocampus as well as determination of the ratio of neurons in cortical and hippocampal regions in neonatal ovariectomized rats. Thirty female rats (one day old) ...
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This study was conducted to evaluate the effect of soy milk on serum 17- β estradiol level and number of neurons in cerebral cortex and hippocampus as well as determination of the ratio of neurons in cortical and hippocampal regions in neonatal ovariectomized rats. Thirty female rats (one day old) were divided into six groups of five. At day 7, ovariectomy surgery was performed in four groups and two other groups were assumed as sham and control groups. Three groups of ovareictomaized rats were fed with soy milk at the doses of 0.75, 1.50 and 3.00 mL kg-1 per day since they were 14. At day 60, the blood samples were collected to measure the17- β estradiol concentration, and then the brain of rats were prepared for histological studies. The serum 17- β estradiol level significantly increased in ovariectomized rats fed with soy milk compared to ovariectomized rats with no soy milk supplementation. In addition, the results showed that soy milk significantly increased the number of neurons in CA1, CA2 and dentate gyrus regions of hippocampus and granular layer of cerebral cortex in ovariectomized rats, whereas there was no significant change in number of neurons in CA3 zone of hippocampus and molecular, pyramidal and multiform layers of cerebral cortex in ovariectomized rats fed with soy milk. The ratio of cerebral cortex neurons to hippocampal neurons had no significant changes among the experimental groups.
Pathology
Masoumeh Moradi-Arzeloo; Amir Abbas Farshid; Esmaeal Tamaddonfard; Siamak Asri-Rezaei
Volume 7, Issue 1 , March 2016, , Pages 47-54
Abstract
In the present study, we investigated the effects of histidine and vitamin C (alone or in combination) treatments against isoproterenol (a β-adrenergic receptor agonist)-induced acute myocardial infarction in rats. We used propranolol (a β-adrenergic receptor blocker) to compare the results. ...
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In the present study, we investigated the effects of histidine and vitamin C (alone or in combination) treatments against isoproterenol (a β-adrenergic receptor agonist)-induced acute myocardial infarction in rats. We used propranolol (a β-adrenergic receptor blocker) to compare the results. Rats were given intraperitoneal injections of histidine (40 mg kg-1) and vitamin C (40 mg kg-1) alone and combined daily for 21 days. Propranolol (10 mg kg-1) was orally administered daily for 10 days (from day 11 to day 21). Myocardial infarction was induced by subcutaneous injections of 150 mg kg-1 of isoproterenol at an interval of 24 hr on days 20 and 21. Blood and tissue samples were taken for histopathological and biochemical evaluations following electrocardiography recording on day 21. Isoproterenol elevated ST segment, increased heart weight, heart rate, serum activities of aspartate transaminase, lactate dehydrogenase, creatine kinase-MB and heart tissue content of malondialdehyde, and decreased R wave amplitude and superoxide dismutase and catalase activities of heart tissue. Necrosis, edema and inflammatory cells infiltration were observed in myocardial tissue sections. Our results indicated that histidine and vitamin C alone, and especially in combination prevent isoproterenol-induced cardiotoxicity and have similar protective effects with propranolol. Cardioprotective effects of histidine and vitamin C may be associated with their ability to reduce free radical-induced toxic effects.
Physiology
Mehrzad Foroud; Nasser Vesal
Volume 6, Issue 4 , December 2015, , Pages 313-318
Abstract
The purpose of the present study was to evaluate anti-nociceptive effects of morphine, tramadol, meloxicam and their combinations in rats. Seventy male Wistar rats were divided into seven equal groups and randomly assigned to receive intraperitoneal saline (S) (control group, 1.0 mL kg-1), morphine (MO) ...
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The purpose of the present study was to evaluate anti-nociceptive effects of morphine, tramadol, meloxicam and their combinations in rats. Seventy male Wistar rats were divided into seven equal groups and randomly assigned to receive intraperitoneal saline (S) (control group, 1.0 mL kg-1), morphine (MO) (4.0 mg kg-1), tramadol (TR) (12.5 mg kg-1), meloxicam (ML) (1.0 mg kg-1), tramadol- morphine (TR-MO), meloxicam-morphine (ML-MO) and meloxicam-tramadol (ML-TR) at the same doses. Anti-nociception was evaluated using tail flick latency (TFL) test at 45, 60, 75, 90 and 120 min after drug injection. The TFL was significantly higher in TR and MO groups compared to S group for 90 and 120 min, respectively. No significant change in TFL from baseline values was observed at all time points in ML group. Among rats that received combination of analgesics, those that received TR-MO had significantly greater TFL. There was no significant difference in TFL between ML-TR and ML-MO groups. In conclusion, TR, MO and their combination all provided acceptable anti-nociceptive effects in rats. Meloxicam at the given dosage (1.0 mg kg-1) did not demonstrate any anti-nociceptive effect when evaluated by TFL test.
Physiology
Esmaeal Tamaddonfard; Amir Erfanparast; Mina Taati; Milad Dabbaghi
Volume 5, Issue 1 , March 2014, , Pages 49-54
Abstract
Calcium, through its various channels involves in local, spinal and supra-spinal transmission of pain. In the present study, we investigated the separate and combined treatment effects of verapamil (a calcium channel blocker), morphine (an opioid agonist) and naloxone (an opioid antagonist) on pain in ...
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Calcium, through its various channels involves in local, spinal and supra-spinal transmission of pain. In the present study, we investigated the separate and combined treatment effects of verapamil (a calcium channel blocker), morphine (an opioid agonist) and naloxone (an opioid antagonist) on pain in the orofacial region of rats. Orofacial pain was induced by subcutaneous (SC) injection of formalin (50 µL, 1.5%) into the left upper lip side, and the time durations spent face rubbing with epsilateral forepaw were recorded in three min blocks for a period of 45 min. Formalin induced a biphasic pattern (first phase: 0-3 min; second phase: 15-33 min) of pain. Intraperitoneal (IP) injections of verapamil (2 and 8 mg kg-1) and morphine (2 and 4 mg kg-1) suppressed orofacial pain. Co-administration of sub-analgesic doses of verapamil (0.5 mg kg-1) and morphine (1 mg kg-1) produced second phase analgesia. Both phases of formalin-induced pain were suppressed when an analgesic dose (2 mg kg-1) of verapamil co-administered with a sub-analgesic dose (1 mg kg-1) of morphine. The SC injection of naloxone (2 mg kg-1) alone with no effect on pain intensity, prevented the antinociceptive effects induced by morphine (2 mg kg-1), but not verapamil (2 mg kg-1). The obtained results showed antinociceptive effects for verapamli and morphine on orofacial pain. Co-administrations of verapamil and morphine produced antinociceptive effects. It seems that opioid analgesic system may not have a role in the verapamil-induced antinociception.
Pharmacology
Esmaeal Tamaddonfard
Volume 1, Issue 1 , June 2010, , Pages 1-6
Abstract
In the present study, the effects of intracerebroventricular (ICV) administration of normal saline (control), histamine, mepyramine (a histamine H1-receptor antagonist) and ranitidine (a histamine H2-receptor antagonist) were investigated on the formalin-induced pain in rabbits. Subcutaneous (SC) injection ...
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In the present study, the effects of intracerebroventricular (ICV) administration of normal saline (control), histamine, mepyramine (a histamine H1-receptor antagonist) and ranitidine (a histamine H2-receptor antagonist) were investigated on the formalin-induced pain in rabbits. Subcutaneous (SC) injection of a formalin (100 μl, 5%) solution into the ventral surface of the right hind paw was performed, and the time durations spent licking and biting the injected paw were measured in 10 min blocks for 1 h. The SC injection of formalin produced a short-lasting (10 min) pain response. The ICV injection of histamine at doses of 25, 50 and 100 μg significantly (P < 0.05) decreased the time duration spent licking and biting the injected paw. Mepyramine and ranitidine, used alone produced no effects. The ICV pretreatments with mepyramine and ranitidine at the same dose of 200 μg significantly (P < 0.05) prevented histamine (100 μg, ICV)-induced antinociception. These results indicate that activation of brain histamine with ICV injection of exogenous histamine produces antinociception. Central histamine H1 and H2 receptors may be involved in the centrally administered histamine-induced antinociception in the formalin-induced pain in rabbits.
