title: Central effects of histamine and H1 and H2 receptors agonists and antagonists after intraventricular infusion in fowls.
abstract: In adult fowls (Gallus deomesticus) the effects of histamine H2 and H2 histamine receptors angonists and antagonists infused into the III cerebral ventricle were studied on behaviour, electrocortical activity and body temperature. Histamine produced biphasic effects, i.e. an initial period of electrocortical synchronization was followed by a longer-lasting behavioural stimulation, electrocortical desynchronization and shivering. Body temperature was increased in a dose-dependent manner. Dimaprit, an agonist at H2 receptors, produced behavioural and electrocortical sleep and decreased body temperature whereas, 2-(2-thiazolyl-)-ethyl-amine, an agonist at H1 receptors, behavioural stimulation, electrocortical desynchronization, vocalization and hyperthermia. Cimetidine, an antagonist at H2 receptors, produced intense behavioural stimulation and electrocortical desynchronization accompanied by vocalization, tachypnoea, occasional escape responses and stereotypies. Body temperature was increased. Mepyramine, an antagonist at H1 receptors, produced behavioural and electrocortical sleep and prevented behavioural  excitation elicited by subsequent infusion of histamine and hyperthermia evoked by 2-(2-thiazolyl -ethylamine. Haloperidol, a neuroleptic drug, sharing with mepyramine membrane stabilizing properties, was unable to antagonize histamine-induced behavioural excitation. In conclusion, present experiments provide pharmacological evidence for the existence of H1 and H2 histamine receptors in avian brain and suggest an involvement of histamine H1 and H2 receptors in the control of arousal-sleep and thermoregulatory mechanisms.
mesh_terms: D000818:Animals; D001831:Body Temperature / Q000187:drug effects; D002490:Central Nervous System / Q000187:drug effects*; D002645:Chickens; D004569:Electroencephalography; D006632:Histamine / Q000008:administration & dosage / Q000494:pharmacology; D006634:Histamine H1 Antagonists / Q000008:administration & dosage / Q000494:pharmacology; D006635:Histamine H2 Antagonists / Q000008:administration & dosage / Q000494:pharmacology; D007276:Injections, Intraventricular; D011968:Receptors, Histamine / Q000187:drug effects*; D011969:Receptors, Histamine H1 / Q000187:drug effects*; D011970:Receptors, Histamine H2 / Q000187:drug effects*; D013997:Time Factors
chemical_list: D006634:Histamine H1 Antagonists; D006635:Histamine H2 Antagonists; D011968:Receptors, Histamine; D011969:Receptors, Histamine H1; D011970:Receptors, Histamine H2; D006632:Histamine