Supersensitivity of analgesic responses to alpha 2-adrenergic agonists in genetically hypertensive rats.
This study compared the responsivity of alpha 2-adrenoceptors to agonists in normotensive (WKY) and genetically hypertensive (SH) rats. Clonidine produced a greater degree of analgesia in SH as compared to WKY rats. This analgesia was antagonized by yohimbine. Neither naphazoline nor 4-hydroxy-clonidine produced analgesia in SH or WKY rats. Our results suggest that the analgesic effects of clonidine in SH rats are probably mediated by supersensitive central alpha 2-adrenoceptors.
D000818:Animals; D003000:Clonidine / Q000494:pharmacology; D006973:Hypertension / Q000235:genetics / Q000503:physiopathology*; D008297:Male; D009278:Naphazoline / Q000494:pharmacology; D010146:Pain / Q000503:physiopathology*; D011224:Prazosin / Q000494:pharmacology; D051381:Rats; D011919:Rats, Inbred Strains; D011942:Receptors, Adrenergic, alpha / Q000187:drug effects / Q000502:physiology*; D015016:Yohimbine / Q000494:pharmacology
D011942:Receptors, Adrenergic, alpha; D015016:Yohimbine; D009278:Naphazoline; D003000:Clonidine; D011224:Prazosin