Szabadi E, Gaszner P, Bradshaw C M
Eur J Clin Pharmacol. 1981;19(6):403-8. doi: 10.1007/BF00548582.
Mydriatic responses of the pupil were evoked by locally instilled noradrenaline and methoxamine in eight healthy volunteers. The effects of three single oral doses (25 mg, 50 mg and 100 mg) of amitriptyline and desipramine were compared on the mydriatic responses. Both antidepressants potentiated the mydriasis evoked by noradrenaline; desipramine appeared to be approximately four times more potent than amitriptyline. Both antidepressants antagonised the mydriasis evoked by noradrenaline; desipramine appeared to be approximately four times more potent than amitriptyline. Both antidepressants antagonised the mydriasis evoked by methoxamine, amitriptyline being approximately twice as potent as desipramine. It is suggested that the potentiation of the response to noradrenaline may reflect the blockade of the uptake of noradrenaline into adrenergic nerve terminals, whereas the antagonism of the response to methoxamine may reflect the blockade of postsynaptic alpha-adrenoceptors by the antidepressants. It is argued that the interaction of the antidepressants with adrenergic mechanisms could explain why amitriptyline, a potent anticholinergic agent, causes no significant change in resting pupil diameter, while desipramine, a relatively weaker anticholinergic agent, produces a significant mydriasis.
在八名健康志愿者中，通过局部滴注去甲肾上腺素和甲氧明诱发瞳孔的散瞳反应。比较了阿米替林和地昔帕明三种单次口服剂量（25毫克、50毫克和100毫克）对散瞳反应的影响。两种抗抑郁药均增强了去甲肾上腺素诱发的散瞳作用；地昔帕明的效力似乎比阿米替林强约四倍。两种抗抑郁药均拮抗甲氧明诱发的散瞳作用，阿米替林的效力约为地昔帕明的两倍。提示对去甲肾上腺素反应的增强可能反映了去甲肾上腺素摄取到肾上腺素能神经末梢的阻断，而对甲氧明反应的拮抗可能反映了抗抑郁药对突触后α-肾上腺素受体的阻断。有人认为，抗抑郁药与肾上腺素能机制的相互作用可以解释为什么强效抗胆碱能药物阿米替林不会使静息瞳孔直径发生显著变化，而相对较弱的抗胆碱能药物地昔帕明却会产生显著的散瞳作用。
