Morphine, 5-HT2 and 5-HT3 receptor antagonists reduce c-fos expression in the trigeminal nuclear complex following noxious chemical stimulation of the rat nasal mucosa.

摘要: Noxious chemical stimulation of the rat nasal mucosa induces expression immediate early gene c-fos in trigeminal brainstem neurons. In present study, we applied irritant mustard oil (1%) into left nostril urethane anesthetized rats. Immunohistochemical methods were used to evaluate Fos protein subnuclei interpolaris and caudalis test effects putative analgesics that might depress synaptic transmission neurons related nociception. For this purpose, morphine (3 mg/kg 10 mg/kg), 5-HT2 antagonist ketanserin (0.5 5 mg/kg) 5-HT3 ICS 205-930 (0.1 1 administered intravenously prior noxious stimulation. Pretreatment with any three compounds reduced Fos-like immunoreactivity. The effect was reversible naloxone. reduction immunoreactivity by exogenous speaks favour an opioidergic link modulation orofacial pain nuclei. 5-HT receptor antagonists are most likely mediated via receptors located on primary afferent fibres.