[Effects of alpha adrenoceptor agonists and antagonists on palpebral fissure and lacrimation in mice].
Ip methoxamine (Met), norepinephrine (NE), xylazine (Xyl), and clonidine (Clo) produced dose-related reversal of ptosis induced by reserpine. These agonists had equivalent Emax values, however, the order of potency was: Clo greater than Met approximately NE greater than Xyl. Met-induced antiptotic action was competitively inhibited by prazosin (Pra) (apparent pA2 = 6.86), but not by idazoxan (Ida); Xyl-induced antiptotic action was competitively inhibited by Ida (apparent pA2 = 6.39), but inhibited by Pra in a noncompetitive manner. These results suggested that the eyelids of mice had both alpha-1 and alpha-2 adrenoceptors. In mice lacrimal gland, Met, and NE elicited dose-related lacrimal secretions, however, Xyl and Clo had no such reaction. Lacrimal secretions elicited by Met or NE were inhibited by Pra, but not by Ida. These results suggested that the lacrimal gland of mice had only alpha-1 adrenoceptor.
Department of Pharmacology, Jiangxi Medical College, Nanchang, China.
J H
JH
Qi
B H
BH
Li
D000316:Adrenergic alpha-Agonists / Q000494:pharmacology*; D000317:Adrenergic alpha-Antagonists / Q000494:pharmacology*; D000818:Animals; D005143:Eyelids / Q000187:drug effects*; D005260:Female; D007765:Lacrimal Apparatus / Q000187:drug effects*; D008297:Male; D051379:Mice; D011942:Receptors, Adrenergic, alpha / Q000187:drug effects*; D013666:Tears / Q000378:metabolism
D000316:Adrenergic alpha-Agonists; D000317:Adrenergic alpha-Antagonists; D011942:Receptors, Adrenergic, alpha