Franz D N, Madsen P W
Neurosci Lett. 1982 Feb 12;28(2):211-6. doi: 10.1016/0304-3940(82)90154-9.
Preganglionic sympathetic discharges, evoked by cervical stimulation in spinal cats, were rapidly and markedly enhanced for 1-2 h by aminophylline or isobutylmethylxanthine. Clonidine depressed intraspinal transmission and prevented enhancement by the xanthines; alpha 2-receptor antagonists blocked the effect of clonidine and not only restored but also markedly prolonged the enhancement by the xanthines. The results suggest that the excitability of sympathetic preganglionic neurons is regulated by cyclic AMP through activation of different subtypes of adrenergic receptors that are either positively or negatively coupled to adenylate cyclase.
在脊髓猫中，通过刺激颈部诱发的节前交感神经放电，可被氨茶碱或异丁基甲基黄嘌呤迅速且显著增强1至2小时。可乐定抑制脊髓内传递，并阻止黄嘌呤类药物的增强作用；α2受体拮抗剂可阻断可乐定的作用，不仅恢复了黄嘌呤类药物的增强作用，还显著延长了其增强效果。结果表明，交感神经节前神经元的兴奋性受环磷酸腺苷调节，其机制是通过激活与腺苷酸环化酶呈正性或负性偶联的不同亚型肾上腺素能受体。
