Abstract
Lobeline is a plant alkaloid known to interact with cholinergic system. The effect of lobeline on neuronal alpha 3 beta 4 receptors expressed in COS cells and muscle embryonic alpha beta gamma delta receptors naturally expressed in TE671 cells was studied using a patch clamp technique.
Our results show that lobeline inhibited responses to acetylcholine in human embryonic muscle nicotinic receptor in a pseudo noncompetitive manner. The responses of rat neuronal alpha 3 beta 4 receptors to a low concentration of acetylcholine were potentiated by a mixed occupation mechanism that corresponds to "competitive potentiation".
This potentiation turned into voltage dependent inhibition for alpha 3 beta 4 receptors was activated by a high concentration of acetylcholine.