Masana M I
Acta Physiol Pharmacol Latinoam. 1984;34(3):235-43.
Cholinergic modulation on the regulation of tyrosine hydroxylase was studied in guinea pig atria depolarized with high potassium concentration. In these conditions there was an increment in tyrosine hydroxylase activity as well as in the release of radioactivity from atria preincubated with 3H-noradrenaline. Both effects were concentration-dependent. Incubation in the presence of 10 microM methacholine, 31 microM 1,1 dimethyl-4-phenylpiperazinium iodide (DMPP), 0.15 microM atropine or 83 microM hexamethonium did not affect tyrosine hydroxylase activation by 100 mM K+. The percentage of activation was reduced however, when 7 microM physostigmine (acetylcholinesterase inhibitor) was present during depolarization. This effect is unlikely to be related to the increase of acetylcholine concentration in the interface, but more probably to a direct effect on the enzyme. In conclusion, tyrosine hydroxylase activation induced by 100 mM potassium appears to be unrelated to the stimulation of nicotinic and muscarinic presynaptic receptors.
在高钾浓度使豚鼠心房去极化的情况下，研究了胆碱能对酪氨酸羟化酶调节的作用。在这些条件下，酪氨酸羟化酶活性以及与3H-去甲肾上腺素预孵育的心房中放射性的释放均有所增加。这两种效应均呈浓度依赖性。在10微摩尔甲胆碱、31微摩尔1,1-二甲基-4-苯基哌嗪碘化物（DMPP）、0.15微摩尔阿托品或83微摩尔六甲铵存在的情况下孵育，并不影响100毫摩尔钾对酪氨酸羟化酶的激活作用。然而，当去极化过程中存在7微摩尔毒扁豆碱（乙酰胆碱酯酶抑制剂）时，激活百分比降低。这种效应不太可能与界面处乙酰胆碱浓度的增加有关，而更可能是对该酶的直接作用。总之，100毫摩尔钾诱导的酪氨酸羟化酶激活似乎与烟碱型和毒蕈碱型突触前受体的刺激无关。
