EVIDENCE FOR A 5-HT1D RECEPTOR-MEDIATED HYPOTHERMIC EFFECT OF THE ALPHA(1)-ADRENOCEPTOR AGONIST, SDZ NVI-085, IN GUINEA-PIGS

The alpha(1)-adrenoceptor agonist, SDZ NVI-085 methyl-9-(methylthio)-2 H-naphth[2,3-b]-1,4-oxazine HCl; 1 mg/kg i.p.), decreased body tempera ture of guinea-pigs. Two 5-HT1D receptor antagonists, GR127935 -1,2,4- oxadiazol-3yl)[1,1-biphenyl]-4-carboxamide) and PAPP (p-aminophenyleth yl-m-trifluaromethylphenyl piperazine; both compounds at 1 mg/kg i.p., -30 min) blocked this response, whilst the alpha(1)-adrenoceptor bloc ker prazosin (1 mg/kg i.p.) and the 5-HT1A receptor antagonist, SDZ 21 6-525 (methyl 2-yl)butyl]-1-piperazinyl}1H-indole-2-carboxylate; 1 mg/ kg i.p.) were inactive. Another alpha(1)-adrenoceptor agonist, St 587 -chloro-5-trifluoromethylphenylimino)-imidazoline; 1 mg/kg i.p.) did n ot alter body temperature. SDZ NVI-085-induced hypothermia in guinea-p igs is probably mediated by 5-HT1D receptors.