Synergistic induction of severe hypothermia (poikilothermia) by limbic seizures, acepromazine and physical restraint: role of noradrenergic alpha-1 receptors.
The maintained production of extreme reductions in core temperature (20-22 degrees C) or poikilothermia can be reliably produced by the synergistic interaction of limbic seizures (induced by lithium and pilocarpine), postseizure administration of a single injection of acepromazine, and physical restraint. Administration of the specific and nonspecific dopamine antagonists haloperidol, chlorpromazine, SCH23390, or clozapine did not simulate the effect at clinically effective dosages. Single injections of phentolamine and prazosin but not of propranolol instead of acepromazine following the seizures produced the poikilothermia. This effect was also reproduced by reducing the amount of the rats' adipose weight before the induction of the seizures and physical restraint. Rats that had been restrained or not restrained and displayed either euthermia or hypothermia exhibited significantly different patterns in brain damage within limbic and thalamic structures.
Persinger
M A
MA
Behavioral Neuroscience Laboratory, Laurentian University, Sudbury, Ontario, Canada P3E 2C6. fl2000002@nickel.laurentian.ca
O'Connor
R P
RP
Bureau
Y R
YR
Parker
G H
GH
Peredery
O
O
Zegil
M
M
D000075:Acepromazine / Q000494:pharmacology*; D058668:Adrenergic alpha-1 Receptor Antagonists; D000818:Animals; D018692:Antimanic Agents; D001831:Body Temperature / Q000187:drug effects / Q000502:physiology; D001921:Brain / Q000187:drug effects / Q000473:pathology / Q000502:physiology; D018492:Dopamine Antagonists / Q000494:pharmacology*; D004305:Dose-Response Relationship, Drug; D004357:Drug Synergism; D007035:Hypothermia / Q000139:chemically induced / Q000209:etiology* / Q000503:physiopathology*; D008032:Limbic System / Q000187:drug effects* / Q000473:pathology / Q000502:physiology; D018021:Lithium Chloride; D008297:Male; D018721:Muscarinic Agonists; D010862:Pilocarpine; D051381:Rats; D017208:Rats, Wistar; D018340:Receptors, Adrenergic, alpha-1 / Q000502:physiology*; D012149:Restraint, Physical; D012640:Seizures / Q000139:chemically induced*
D058668:Adrenergic alpha-1 Receptor Antagonists; D018692:Antimanic Agents; D018492:Dopamine Antagonists; D018721:Muscarinic Agonists; D018340:Receptors, Adrenergic, alpha-1; D010862:Pilocarpine; D000075:Acepromazine; D018021:Lithium Chloride