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Role of 5‐hydroxytryptamine in ketamine‐induced hypothermia in the rat
Author(s) -
FAHIM I.,
ISMAIL M.,
OSMAN O. H.
Publication year - 1973
Publication title -
british journal of pharmacology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.432
H-Index - 211
eISSN - 1476-5381
pISSN - 0007-1188
DOI - 10.1111/j.1476-5381.1973.tb08243.x
Subject(s) - ketamine , hypothermia , reserpine , pargyline , hyperthermia , monoamine neurotransmitter , chemistry , serotonin , morphine , pharmacology , intraperitoneal injection , tetrabenazine , endocrinology , anesthesia , medicine , dopamine , receptor
Summary1 Intraperitoneal injection of graded doses of ketamine produced a dose‐dependent fall in body temperature of rats. Similarly, intracerebral injection of much smaller doses produced hypothermia. 2 Pretreatment of the rats with p ‐chlorophenylalanine (PCPA) greatly attenuated the hypothermic response to ketamine whereas the intraperitoneal injection of 5‐hydroxytryptophan in PCPA‐treated rats restored the hypothermic effect of ketamine. 3 Depletion of the brain monoamines by reserpine completely prevented the ketamine‐induced hypothermia. Treatment with sodium diethyldithiocarbamate (DEDTC), however, did not modify the hypothermic effect of ketamine. 4 Pretreatment of the rats with pargyline potentiated the ketamine‐induced hypothermia. 5 Depletion of brain monoamines by reserpine in combination with inhibition of noradrenaline biosynthesis (DEDTC) resulted in a long lasting fall in temperature which was not modified by ketamine. 6 When the ambient temperature was raised from 26° C to 32° C, ketamine‐induced hypothermia was much reduced and superimposed on a hyperthermia which occurred in all animals. 7 It is concluded that ketamine produces hypothermia in rats possibly through the release of 5‐hydroxytryptamine in the hypothalamus and that this effect is similar in some respects to that produced by morphine in non‐tolerant rats.