Nayler W G
Br J Pharmacol. 1972 Jun;45(2):382-4. doi: 10.1111/j.1476-5381.1972.tb08094.x.
Inotropic dose-response curves were constructed for a series of beta-adrenoceptor antagonists, based on the inotropic responses of isolated dog trabecular muscles stimulated to contract at a regular rate. Propranolol exerted only a negative inotropic effect but K01366, LB46, oxprenolol and practolol all evoked a positive inotropic response, whether or not catecholamine-depleted muscles were used. The order of potency for this positive inotropic activity was K01366>LB46>oxprenolol>practolol. The duration of the positive inotropic response to the antagonists was more prolonged than that due to isoprenaline. Propranolol significantly reduced the positive inotropic response to K01366, LB46, oxprenolol and practolol.
基于以恒定速率刺激收缩的离体犬小梁肌的变力反应,构建了一系列β-肾上腺素能受体拮抗剂的变力剂量反应曲线。普萘洛尔仅产生负性变力作用,但无论是否使用去甲肾上腺素耗竭的肌肉,K01366、LB46、氧烯洛尔和普拉洛尔均能引发正性变力反应。这种正性变力活性的效价顺序为K01366>LB46>氧烯洛尔>普拉洛尔。拮抗剂产生的正性变力反应持续时间比异丙肾上腺素引起的更长。普萘洛尔显著降低了对K01366、LB46、氧烯洛尔和普拉洛尔的正性变力反应。