Brown D A, Dunn P M
Br J Pharmacol. 1983 Jun;79(2):429-39. doi: 10.1111/j.1476-5381.1983.tb11016.x.
Depolarizations of freshly-dissected isolated superior cervical ganglia of the rat were recorded extracellularly. The following sympathomimetic amines (in order of decreasing potency) produced depolarizations of up to 0.4 mV: isoprenaline, salbutamol, adrenaline, noradrenaline. Depolarizations were lost after overnight storage, leaving only hyperpolarizing responses. Depolarizations by isoprenaline were antagonized by (-)-propranolol (pA2 8.94 +/- 0.15), (+/-)-butoxamine (pA2 7.36 +/- 0.12) and (+/-)-practolol (pA2 5.14 +/- 0.13). They were not blocked by phentolamine (1 microM) or phenoxybenzamine (1 microM). Isoprenaline and salbutamol were antagonized with equal facility by practolol or butoxamine. In concentrations producing ganglionic depolarization, these compounds also produced a smaller depolarization of presynaptic elements in the ganglion, but not preganglionic trunk fibres. Presynaptic depolarization was blocked by 100 nM propranolol but not by 1 microM phentolamine. Isoprenaline and salbutamol increased the amplitude of the compound ganglionic action potential recorded following single preganglionic nerve stimuli when transmission had been rendered submaximal by adjusting the Ca/Mg ratio, but not in normal solution. Isoprenaline (0.1 microM) also increased the amount of [3H]-acetylcholine released by preganglionic stimulation in low Ca/high Mg solution. It is concluded that facilitatory adrenoceptors are present on pre- and postsynaptic elements in rat superior cervical ganglia, which resembles the 'beta 2' subclass of beta-receptors.
采用细胞外记录法，记录了刚解剖的大鼠离体颈上神经节的去极化情况。以下拟交感胺（按效力递减顺序排列）可产生高达0.4 mV的去极化：异丙肾上腺素、沙丁胺醇、肾上腺素、去甲肾上腺素。过夜储存后去极化消失，仅留下超极化反应。异丙肾上腺素引起的去极化可被（-）-普萘洛尔（pA2 8.94±0.15）、（±）-布托沙明（pA2 7.36±0.12）和（±）-普拉洛尔（pA2 5.14±0.13）拮抗。它们不受酚妥拉明（1 μM）或酚苄明（1 μM）的阻断。普拉洛尔或布托沙明对异丙肾上腺素和沙丁胺醇的拮抗作用相同。在产生神经节去极化的浓度下，这些化合物也会使神经节中突触前成分产生较小的去极化，但不会使节前干纤维产生去极化。突触前去极化可被100 nM普萘洛尔阻断，但不受1 μM酚妥拉明的阻断。当通过调整钙/镁比例使传递变得次最大时，异丙肾上腺素和沙丁胺醇会增加单个节前神经刺激后记录的复合神经节动作电位的幅度，但在正常溶液中则不会。异丙肾上腺素（0.1 μM）还会增加低钙/高镁溶液中节前刺激释放的[3H]-乙酰胆碱的量。结论是，大鼠颈上神经节的突触前和突触后成分上存在易化性肾上腺素能受体，类似于β受体的“β2”亚类。
