Heterogeneity of presynaptic muscarinic receptors located on different tissue preparations.
Three different tissue preparations were used to demonstrate the heterogeneity of presynaptic muscarinic receptors that modulate neurotransmitter release. The presynaptic antimuscarinic potency of several muscarinic antagonists was characterized with the enhancement of the neurotransmitter release evoked by electrical stimulation on the guinea-pig ileum Auerbach plexus, the guinea-pig atrium and the rat brain cortex. Presynaptic muscarinic receptors located on the Auerbach plexus proved to be different of those present on the cortical cholinergic interneurons and on the sympathetic plexus of the guinea-pig atrium.
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