Benfey B G
Br J Pharmacol. 1977 Oct;61(2):167-73. doi: 10.1111/j.1476-5381.1977.tb08401.x.
1 The hypothesis that low temperature converts inotropic beta-adrenoceptors to alpha-adrenoceptors has been tested in isolated heart preparations of the frog and rat. 2 The results do not support the adrenoceptor interconversion hypothesis. In the frog ventricle strip lowering the temperature from 24 degrees C to 14 degrees C did not significantly alter the inotropic potency of the sympathomimetic drugs isoprenaline, adrenaline and phenylephrine and did not reduce the potency of the beta-adrenoceptor blocking drug propranolol as an isoprenaline antagonist. In the isolated left atrium of the rat lowering the temperature from 31 degrees C and 24 degrees C to 17-19 degrees C did not significantly alter the inotropic potency of isoprenaline, noradrenaline and phenylephrine, did not diminish the potency of the beta-adrenoceptor blocking drug propranolol and did not increase the potency of the alpha-adrenoceptor blocking drug phentolamine. 3 Phenylephrine acted on alpha- and beta-adrenoceptors in rat left atrium at 31 degrees C and 24 degrees C, but only on beta-adrenoceptors at 17-19 degrees C.
1 低温将变力性β-肾上腺素能受体转变为α-肾上腺素能受体这一假说已在青蛙和大鼠的离体心脏标本中进行了检验。2 结果不支持肾上腺素能受体相互转化假说。在青蛙心室肌条中，将温度从24℃降至14℃并未显著改变拟交感神经药物异丙肾上腺素、肾上腺素和去氧肾上腺素的变力效能，也未降低β-肾上腺素能受体阻断药普萘洛尔作为异丙肾上腺素拮抗剂的效能。在大鼠离体左心房中，将温度从31℃和24℃降至17 - 19℃并未显著改变异丙肾上腺素、去甲肾上腺素和去氧肾上腺素的变力效能，未降低β-肾上腺素能受体阻断药普萘洛尔的效能，也未增加α-肾上腺素能受体阻断药酚妥拉明的效能。3 去氧肾上腺素在31℃和24℃时作用于大鼠左心房的α和β肾上腺素能受体，但在17 - 19℃时仅作用于β肾上腺素能受体。
