Analysis of hypothermic response to centrally administered histamine in pigeons.
The effect of intracerebroventricular (i.c.v.) administration of histamine (H), H1- and H2-receptor agonists and their antagonists, on the cloacal temperature of pigeon has been investigated. Histamine produced a dose-dependent hypothermia at an ambient temperature of 24 degrees C which was significantly blocked by a combination of mepyramine and cimetidine but was only partially antagonized by either of them alone. H1-receptor as well as H2-receptor agonists also produced hypothermic response with a time-course similar to that of H. Their effects were also significantly antagonized by mepyramine and cimetidine respectively. The histamine response was not modified by pretreatment with alpha- or beta-adrenoceptor antagonists. Histamine produced an insignificant hyperthermia at 10 degrees C but the hypothermic effect increased as the ambient temperature was raised up to 40 degrees C. It is concluded that both H1- and H2-histamine receptors are present in the brain of pigeon and are responsible for H-induced hypothermia.
D000818:Animals; D001831:Body Temperature / Q000187:drug effects*; D001833:Body Temperature Regulation; D010856:Columbidae / Q000502:physiology*; D004305:Dose-Response Relationship, Drug; D005260:Female; D006632:Histamine / Q000494:pharmacology*; D008297:Male; D011941:Receptors, Adrenergic / Q000502:physiology; D011968:Receptors, Histamine / Q000502:physiology*; D011969:Receptors, Histamine H1 / Q000502:physiology; D011970:Receptors, Histamine H2 / Q000502:physiology; D013696:Temperature
D011941:Receptors, Adrenergic; D011968:Receptors, Histamine; D011969:Receptors, Histamine H1; D011970:Receptors, Histamine H2; D006632:Histamine