Hypothermia elicited by some prodynorphin-derived peptides: Opioid and non-opioid actions

The dynamic relationship between mu and kappa opioid receptors in body temperature regulation

“…Previous studies showed that icv injection of mu opioid receptor agonists (i.e. PL017, morphine, DAMGO) in rats produces hyperthermia which is blocked by icv injection of the mu opioid receptor antagonists CTAP or beta-FNA Appelbaum and Holtzman, 1986;Bradley et al, 1991;Handler et al, 1992Handler et al, , 1994Spencer et al, 1988), and that icv injection of the kappa opioid receptor agonists, dynorphin, U50,488H, U69,593, dynorphin or spiradoline, induces hypothermia in rats which can be blocked by the kappa opioid receptor antagonist nor-BNI Adler et al, 1983;Cavicchini et al, 1988Cavicchini et al, , 1989Handler et al, 1992Handler et al, , 1994Spencer et al, 1988). These results demonstrated that hyperthermia induced by opioid agonists is mediated by the mu opioid receptor and hypothermia induced by opioid agonists is mediated by kappa opioid receptors in the brain.…”

“…Mu opioid agonists, such as morphine, DAMGO or PL017, given icv or directly into the preoptic anterior hypothalamus in rats, produce hyperthermia which is blocked by icv injection of the mu-selective antagonist CTAP or h-FNA (Appelbaum and Holtzman, 1986;Bradley et al, 1991;Handler et al, 1992Handler et al, , 1994Spencer et al, 1988). Icv injection of the kappa opioid receptor agonists dynorphin A 1 -17 , U50,488H, U69,593 or spiradoline induces hypothermia in rats Adler et al, 1983;Cavicchini et al, 1988Cavicchini et al, , 1989Spencer et al, 1988) and the kappa-selective antagonist nor-BNI can block the hypothermic effect Adler et al, 1983;Cavicchini et al, 1988;Cavicchini et al, 1989;Handler et al, 1992Handler et al, , 1994Spencer et al, 1988). The successful cloning of the mu , delta (Evans et al, 1992;Kieffer et al, 1992) and kappa (Li et al, 1993;Yakimova et al, 1998;Yasuda et al, 1993) opioid receptors have allowed the use of antisense oligodeoxynucleotide to explore functions of these opioid receptor systems.…”

Behavioral Characterization of κ Opioid Receptor Agonist Spiradoline and Cannabinoid Receptor Agonist CP55940 Mixtures in Rats

“…Hypothermic effects have been reported for the k opioid receptor agonists U50488, U69593, and salvinorin A (Hayes et al, 1985;Cavicchini et al, 1989;Nemmani et al, 2001;Baker and Meert, 2002), and there is a report of spiradoline producing hypothermia after intracerebroventricular administration (Adler and Geller, 1993). The present study generated full dose-response functions for the hypothermic effects of spiradoline after i.p.…”

Hypothermia after cesarean delivery and its reversal with lorazepam

“…Some investigators have found naloxone, a l-receptor antagonist, to be effective in treating hypothermia, while others have found no effect. 2,17 Other investigators have suggested that the j-receptor may be the primary mechanism of opioid-induced hypothermia. 3,17,18 Because stress appears to be a common element for the induction of hypothermia in animals, Rio-Garcia and Cremades 1 investigated the GABAergic mechanism of morphineinduced hypothermia in rats.…”

“…2,17 Other investigators have suggested that the j-receptor may be the primary mechanism of opioid-induced hypothermia. 3,17,18 Because stress appears to be a common element for the induction of hypothermia in animals, Rio-Garcia and Cremades 1 investigated the GABAergic mechanism of morphineinduced hypothermia in rats. They found that pretreatment with diazepam prevented morphine-induced hypothermia in rats, while flumazenil, a benzodiazepine antagonist, potentiated the hypothermic action of morphine.…”