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Peptide cotransmitter at a neuromuscular junction.
Science (New York, N.Y.)
|July 15, 1983
Summary
The neuropeptide proctolin is released by cockroach neurons to cause muscle contractions. This suggests proctolin functions as a cotransmitter, producing delayed muscle effects without depolarization.
Area of Science:
- Neuroscience
- Insect Physiology
- Molecular Biology
Background:
- Proctolin is a neuropeptide found in the nervous system.
- Its role in insect muscle function is under investigation.
Purpose of the Study:
- To investigate the function of the neuropeptide proctolin in cockroach skeletal muscle.
- To determine if proctolin acts as a cotransmitter in neuromuscular signaling.
Main Methods:
- Identified a slow skeletal motoneuron in the cockroach.
- Stimulated neuron and used potassium depolarization to release proctolin.
- Measured muscle contractile effects.
Main Results:
- Proctolin is present in nerve terminals innervating the coxal depressor muscle.
- Proctolin release was induced by neural stimulation and potassium depolarization.
- Proctolin and neural stimulation caused delayed, sustained muscle contractions without depolarization.
Conclusions:
- Proctolin acts as a cotransmitter in the identified motoneuron.
- Proctolin mediates delayed and sustained contractile effects on slow skeletal muscle.