Smith P G, Beauregard C L
Department of Physiology, University of Kansas Medical Center, Kansas City 66160-7401.
Brain Res. 1993 Dec 3;629(2):319-22. doi: 10.1016/0006-8993(93)91338-s.
Parasympathetic innervation of rat periorbital smooth muscle normally inhibits excitatory sympathetic neurotransmission but does not directly affect muscle tone. Five weeks after sympathetic denervation, however, parasympathetic stimulation now elicits contractions. These are blocked by atropine, indicating establishment of muscarinic cholinergic neuromuscular transmission. Conversion to excitation is not accompanied by enhanced smooth muscle responsiveness to muscarinic stimulation, indicating that prejunctional alterations are responsible.
大鼠眶周平滑肌的副交感神经支配通常会抑制兴奋性交感神经传递，但不会直接影响肌张力。然而，在交感神经去神经支配五周后，副交感神经刺激现在会引起收缩。这些收缩被阿托品阻断，表明毒蕈碱型胆碱能神经肌肉传递已经建立。向兴奋的转变并不伴随着平滑肌对毒蕈碱刺激反应性的增强，这表明是节前改变所致。
