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.
Amir Erfanparast; Esmaeal Tamaddonfard; Farzin Henareh-Chareh
Volume 11, Issue 3 , September 2020, , Pages 229-234
Abstract
Previous findings have shown that saffron (Crocus sativus L.) extract and its active constituents produce antinociceptive effects in the rat models of orofacial pain. In the present study, the central H2 histaminergic and alpha-2 adrenergic receptors involvement in crocetin-induced antinociception ...
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Previous findings have shown that saffron (Crocus sativus L.) extract and its active constituents produce antinociceptive effects in the rat models of orofacial pain. In the present study, the central H2 histaminergic and alpha-2 adrenergic receptors involvement in crocetin-induced antinociception in orofacial formalin pain in rats was evaluated.The guide cannula was implanted into the fourth ventricle in ketamine-xylazine anesthetized rats. Subcutaneous injection of a diluted formalin solution (1.50%; 50.00 µL) into a vibrissa pad was used as a model of orofacial pain. Face rubbing behavior durations were recorded at 3 min blocks for 45 min.Formalin produced a biphasic pain response (first phase: 0-3 min and second phase: 15-33 min). Intra-fourth ventricle injections of crocetin (5.00 and 10.00 μg μL-1) suppressed, whereas yohimbine (10.00 μg μL-1) and naloxone (10.00 μg μL-1) increased the intensity of both phases of pain. Crocetin-induced antinociception was not prevented by central pretreatment with naloxone. However, the antinociceptive effect of crocetin (5.00 μg μL-1) was inhibited by prior administration of famotidine (10.00 μg μL-1) and yohimbine (10.00 μg μL-1). Our study showed that injection of crocetin into the cerebral fourth ventricle attenuated formalin-induced orofacial pain in rats. Central H2 histaminergic and alpha-2 adrenergic receptors, but not opioid receptors, might be involved in crocetin-induced antinociception.