kappa-opioid receptor-mediated analgesia: hotplate temperature and sex differences.
The present experiment was designed to investigate the dose-effect and time-effect functions of the kappa-opioid receptor agonist [5alpha,7alpha, 8beta)-(-)-N-Methyl-N-[7-(1-pyrrolidinyl)-1-oxaspiro(4, 5)dec-8-yl]benzeneacetamide] (U69,593) in intact and gonadectomized male and female rats as a function of hotplate temperature (45 degrees C or 51 degrees C). At 45 degrees C baseline lick latencies were longer in female rats than in male rats. Lick latencies increased dose-dependently in all subjects except intact female rats. U69,593 increased lick latencies as a function of time since its administration in all subjects. At 51 degrees C baseline lick latencies did not differ between groups and they increased dose-dependently in all subjects. The effectiveness of U69,593 decreased as a function of time since its administration, but not in castrated male rats. These observations suggest that gonadal hormones could play a role in modulating the behavioral effects of U69,593 when subjects are tested at different hotplate temperatures.
van Haaren
F
F
Department of Psychology, University of Florida, Gainesville, FL 32611-2250, USA. haaren@psych.ufl.edu
Scott
S
S
Tucker
L B
LB
D000700:Analgesics / Q000494:pharmacology*; D000818:Animals; D044482:Benzeneacetamides; D004305:Dose-Response Relationship, Drug; D005260:Female; D006358:Hot Temperature / Q000009:adverse effects*; D008297:Male; D009919:Orchiectomy; D010052:Ovariectomy; D010147:Pain Measurement / Q000187:drug effects*; D011759:Pyrrolidines / Q000494:pharmacology*; D051381:Rats; D017207:Rats, Sprague-Dawley; D017473:Receptors, Opioid, kappa / Q000187:drug effects* / Q000502:physiology; D012737:Sex Factors; D013997:Time Factors
D000700:Analgesics; D044482:Benzeneacetamides; D011759:Pyrrolidines; D017473:Receptors, Opioid, kappa; C045444:U 69593