Beal A M
School of Biological Science, University of New South Wales, 2052, Sydney, Australia.
Arch Oral Biol. 2000 Aug;45(8):701-6. doi: 10.1016/s0003-9969(00)00033-9.
Selective and non-selective beta-adrenoceptor antagonists were used to block the increases in fluid and protein secretion caused by sympathomimetic stimulation of the mandibular gland of red kangaroos during intracarotid infusion of isoprenaline. Atenolol or ICI118551 at antagonist:agonist ratios up to 300:1 caused increasing but incomplete blockade of fluid secretion and protein release. Both selective antagonists had equal potency and both antagonists were more effective at blocking protein release than at blocking fluid secretion. Consequently, the mechanisms underpinning fluid secretion are more sensitive to beta-sympathomimetic stimulation than those causing protein release. Propranolol at antagonist:agonist ratios of 300:1 was more potent than the selective antagonists, almost totally blocking the increases in fluid secretion and protein release. The data are consistent with the acini of the kangaroo mandibular gland having both beta(1)- and beta(2)-adrenoceptors and with the increased fluid secretion and protein release by isoprenaline being mediated by both receptor subtypes.
在颈内动脉输注异丙肾上腺素期间，使用选择性和非选择性β - 肾上腺素能受体拮抗剂来阻断拟交感神经刺激红袋鼠下颌腺所引起的液体和蛋白质分泌增加。阿替洛尔或ICI118551在拮抗剂与激动剂比例高达300:1时，对液体分泌和蛋白质释放的阻断作用逐渐增强，但并不完全。两种选择性拮抗剂效力相当，且两者在阻断蛋白质释放方面比阻断液体分泌更有效。因此，支撑液体分泌的机制比引起蛋白质释放的机制对β - 拟交感神经刺激更敏感。普萘洛尔在拮抗剂与激动剂比例为300:1时比选择性拮抗剂更有效，几乎完全阻断了液体分泌和蛋白质释放的增加。这些数据表明，袋鼠下颌腺的腺泡同时具有β(1) - 和β(2) - 肾上腺素能受体，并且异丙肾上腺素引起的液体分泌和蛋白质释放增加是由两种受体亚型介导的。
