Boyd G, Gillespie J S, Mackenna B R
Br J Pharmacol Chemother. 1962 Oct;19(2):258-70. doi: 10.1111/j.1476-5381.1962.tb01187.x.
The effect of guanethidine and of bretylium on the response to nerve stimulation has been studied on two types of isolated innervated preparations of rabbit intestine. One preparation was that of the rabbit ileum in which the periarterial (mainly sympathetic) nerves were stimulated: the other was the doubly innervated rabbit colon where either parasympathetic (pelvic) or sympathetic (lumbar colonic) nerves were stimulated. In both preparations guanethidine and bretylium in appropriate dosage specifically blocked the inhibitory effect of sympathetic nerve stimulation while leaving the response to parasympathetic nerve stimulation and to acetylcholine unaltered: the response to noradrenaline was unaltered or potentiated. In the ileum, after the addition of guanethidine or of bretylium, the inhibitory response to periarterial nerve stimulation was replaced in every preparation by a motor response which had the same frequency sensitivity as parasympathetic nerves. In the colon a motor response to sympathetic nerve stimulation was rarely obtained after blocking the inhibitory response. When such a motor response was uncovered it had similar characteristics to the motor response in the ileum. Furthermore, if the parasympathetic nerves were stimulated for prolonged periods both the parasympathetic and sympathetic motor responses were reduced. These results do not support the idea that post-ganglionic sympathetic nerves to the intestine are generally cholinergic and are themselves responsible for the motor responses. The experimental results are more conveniently explained by assuming a mixture of cholinergic and adrenergic fibres in the nerves stimulated.
已在两种类型的兔肠离体神经支配标本上研究了胍乙啶和溴苄铵对神经刺激反应的影响。一种标本是兔回肠，刺激其动脉周围（主要是交感）神经；另一种是双重神经支配的兔结肠，刺激其副交感（盆部）或交感（腰结肠）神经。在这两种标本中，适当剂量的胍乙啶和溴苄铵能特异性阻断交感神经刺激的抑制作用，而对副交感神经刺激和乙酰胆碱的反应无改变：对去甲肾上腺素的反应无改变或增强。在回肠中，加入胍乙啶或溴苄铵后，每个标本中对动脉周围神经刺激的抑制反应均被一种运动反应所取代，该运动反应具有与副交感神经相同的频率敏感性。在结肠中，阻断抑制反应后很少能获得对交感神经刺激的运动反应。当出现这种运动反应时，其特征与回肠中的运动反应相似。此外，如果长时间刺激副交感神经，副交感和交感运动反应均会减弱。这些结果不支持这样的观点，即支配肠道的节后交感神经一般是胆碱能的，且其自身负责运动反应。通过假设受刺激神经中存在胆碱能和肾上腺素能纤维的混合，能更方便地解释实验结果。
