The effects of intraventricular 6-hydroxydopamine on body temperature and arterial blood pressure in cats and rabbits.
1 In unanaesthetized cats, the administration of 6-hydroxydopamine (6-OHDA), 750 mug, via the lateral cerebral ventricle produced a pronounced fall in rectal temperature but only a slight fall when repeated 7 days later. At this time hypothalamic noradrenaline concentration had diminished to 4% of control.2 In these animals, the hypothermic response to exogenous noradrenaline, 100 mug, given via the same route was uninfluenced by pretreatment with 6-OHDA.3 In unanaesthetized rabbits, intraventricular noradrenaline, 100 mug, produced a rise in rectal temperature and a biphasic effect on arterial pressure, a rise lasting 30 min followed by a fall.4 Intraventricular 6-OHDA, 750 mug, in unanaesthetized rabbits produced a rise in body temperature and a rise in arterial pressure. The same dose given to rabbits depleted of central noradrenaline with central 6-OHDA produced rises in body temperature and arterial pressure of similar magnitude, but of slower onset.5 These results suggest that intraventricular 6-OHDA releases noradrenaline from central neurones and that these neurones subserve thermoregulatory functions in both species. In the rabbit, central noradrenergic neurones can raise arterial pressure.
D000818:Animals; D001794:Blood Pressure / Q000187:drug effects*; D001831:Body Temperature / Q000187:drug effects*; D001923:Brain Chemistry / Q000187:drug effects; D002415:Cats; D002552:Cerebral Ventricles; D003864:Depression, Chemical; D006892:Hydroxydopamines / Q000008:administration & dosage / Q000494:pharmacology*; D007267:Injections; D007275:Injections, Intravenous; D009638:Norepinephrine / Q000037:antagonists & inhibitors / Q000494:pharmacology; D011817:Rabbits; D013045:Species Specificity; D013997:Time Factors
D006892:Hydroxydopamines; D009638:Norepinephrine