Probable mechanism of action of methyldopa on cholinergically innervated tissues

Methyldopa (200 and 400 micrograms/ml) induced an increase in the responsiveness of guinea-pig ileum to ACh after incubation for 1 hr 15 min. However, no such effect was observed in the case of frog rectus abdominis muscle. It is suggested that methyldopa influences receptor mechanisms associated with cholinergic muscarinic but not nicotinic receptors.