Cholera and pertussis toxins inhibit differently hypothermic and anti-opioid effects of neuropeptide FF.
In mice pretreated intracerebroventricularly (i.c.v.) with pertussis or cholera toxins, effects of neuropeptide FF (NPFF), on hypothermia and morphine-induced analgesia, were assessed. NPFF and a potent NPFF agonist, 1DMe (0.005-22 nmol) injected into the lateral ventricle decreased morphine analgesia and produced naloxone (2.5 mg x kg(-1), s.c.)-resistant hypothermia after administration into the third ventricle. Cholera toxin (CTX 1 microg, i.c.v.) pretreatment (24 or 96 h before) inhibited the effect of 1DMe on body temperature, but failed to reverse its anti-opioid activity in the tail-flick test. CTX reduced hypothermia induced by a high dose of morphine (8 nmol, i.c.v.) but not the analgesic effect due to 3 nmol morphine. Pertussis toxin (PTX) pretreatment inhibited both morphine-hypothermia and -analgesia but did not modify hypothermia induced by 1DMe. The present results suggest that NPFF-induced hypothermia depends on the stimulation of Gs (but not Gi) proteins. In contrast, anti-opioid effects resulting from NPFF-receptor stimulation do not involve a cholera toxin-sensitive transducer protein.
Francés
B
B
Institut de Pharmacologie et de Biologie Structurale, CNRS, 205 Route de Narbonne, 31077 Cedex, Toulouse, France.
Lahlou
H
H
Zajac
J M
JM
D000818:Animals; D002772:Cholera Toxin / Q000494:pharmacology*; D007036:Hypothermia, Induced; D008297:Male; D051379:Mice; D009020:Morphine / Q000494:pharmacology; D009292:Narcotic Antagonists / Q000494:pharmacology*; D009294:Narcotics / Q000494:pharmacology; D009842:Oligopeptides / Q000494:pharmacology*; D010147:Pain Measurement / Q000187:drug effects; D037342:Pertussis Toxin; D018013:Receptors, Neuropeptide / Q000187:drug effects; D012018:Reflex / Q000187:drug effects; D013623:Tail; D010566:Virulence Factors, Bordetella / Q000494:pharmacology*
D009292:Narcotic Antagonists; D009294:Narcotics; D009842:Oligopeptides; D018013:Receptors, Neuropeptide; D010566:Virulence Factors, Bordetella; C083929:neuropeptide FF receptor; C105455:neuropeptide FF, Tyr(1)-N-methyl-Phe(3)-; D009020:Morphine; D002772:Cholera Toxin; C053651:phenylalanyl-leucyl-phenylalanyl-glutaminyl-prolyl-glutaminyl-arginyl-phenylalaninamide; D037342:Pertussis Toxin