Blocking of muscarinic receptors does not affect post tetanic response in frog neuromuscular junction

Abstract

Post-tetanic potentiation (PTP) is an often-studied form of synaptic plasticity that is associated with motor learning. Although the exact physiological mechanism is as yet unknown, there is some evidence that muscarinic receptors may play a role in this process, as muscarinic antagonists have been shown to prevent the induction of long-term potentiation by tetanic stimulation. However, after observing the effects of the general muscarinic inhibitor atropine on the end-plate potentials (EPPs) of the frog sartorius muscle, we report preliminary data suggesting that muscarinic receptors do not play a significant role in the induction of PTP. Observations of the amplitude of the EPPs suggest that muscarinic receptors do play a role in the modulation of neurotransmitter (NT) release in the neuromuscular junction (NMJ), as evidenced by the decrease in EPP amplitude in the presence of the muscarinic antagonist atropine.