Calcitonin gene-related peptide excites myenteric neurons

Eur J Pharmacol. 1986 Dec 16;132(2-3):163-70. doi: 10.1016/0014-2999(86)90601-1.

Abstract

Intracellular methods were used to record electrical behavior of myenteric neurons in guinea-pig ileum in vitro. Calcitonin gene-related peptide (CGRP; 1 nM to 1 microM) and calcitonin (1-100 microM) were applied by addition to the superfusion solution of longitudinal muscle-myenteric plexus preparations. Both peptides were applied also by pressure ejection from fine-tipped micropipettes. CGRP, applied by either method, evoked a long-lasting depolarization of the cell membranes that was dose-dependent (ED50 = 50 nM) and was associated with an increase in the input resistance, suppression of post-spike hyperpolarizing potentials and enhanced excitability in all neurons that were tested. The enhanced excitability was reflected by a significant increase in the number of action potentials evoked by intracellular injection of constant current depolarizing pulses. Enhanced excitability also was apparent as a train of spikes that appeared at the crests of the CGRP-induced depolarization. The excitatory action of CGRP simulated slow synaptic excitation. Application of calcitonin did not evoke any changes in electrical behavior of myenteric neurons. The results are consistent with a neurotransmitter or neuromodulator role for CGRP in the enteric nervous system and suggest that it may participate in local neurohumoral regulation of gastrointestinal effector systems.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Action Potentials / drug effects
  • Animals
  • Calcitonin / pharmacology
  • Calcitonin Gene-Related Peptide
  • Guinea Pigs
  • In Vitro Techniques
  • Membrane Potentials / drug effects
  • Microinjections
  • Muscle, Smooth / drug effects
  • Myenteric Plexus / drug effects*
  • Neurons / drug effects*
  • Neuropeptides / pharmacology*

Substances

  • Neuropeptides
  • Calcitonin
  • Calcitonin Gene-Related Peptide