Synaptic and Hormonal Modulation of A Neuronal Oscillator: A Search for Molecular Mechanisms
Open Access
- 1 August 1979
- journal article
- Published by The Company of Biologists in Journal of Experimental Biology
- Vol. 81 (1), 131-151
- https://doi.org/10.1242/jeb.81.1.131
Abstract
The central ganglia of a number of gastropod molluscs (including the marine snail Aplysia californica and the terrestrial snail Helix pomatia) contain neurones which exhibit endogenous patterns of oscillatory activity. This oscillatory activity can be modulated for long periods of time by synaptic and hormonal stimulation. Stimulation of appropriate pre-synaptic nerves causes long-lasting hyperpolarization in these neurones, with complete abolition of oscillatory activity. This synaptic response is mediated by an increase in K+ conductance, together with a decrease in inward (Na+/Ca2+) conductance. The ionic conductances affected by synaptic stimulation are those responsible for producing the rhythmic oscillations. The oscillatory activity can also be modulated by the vertebrate neurohypophyseal peptides, vasopressin and oxytocin, and by an endogenous peptide-containing extract of molluscan ganglia. In contrast to synaptic stimulation, these agents cause an increase in oscillatory activity. The endogenous molluscan factor which produces an increase in oscillatory activity can be purified by affinity chromatography on bovine neurophysin linked to Sepharose. This indicates that the molluscan nervous system may contain a neurohypophyseal-like peptide. Oscillatory activity can be modulated by manipulation of cyclic nucleotide metabolism in these neurones. Increases in cAMP alone are associated with abolition of oscillatory activity; this mimics long-lasting synaptic hyperpolarization. Increases in cAMP and cGMP together are associated with an increase in oscillatory activity and mimic the effects of the vertebrate and molluscan peptides. Thus, it is possible that cyclic nucleotides play a role in these physiological responses.This publication has 40 references indexed in Scilit:
- Evolution of Active Neurohypophysial Principles Among the VertebratesAmerican Zoologist, 1977
- Oscillations in calcium-cyclic AMP control loops form the basis of pacemaker activity and other high frequency biological rhythmsJournal of Theoretical Biology, 1977
- Diurnal rhythms in cyclic nucleotide metabolism inHelix nervous systemJournal of Neurobiology, 1977
- Patterns of proteins synthesized in the R15 neuron of Aplysia. Temporal studies and evidence for processing.The Journal of general physiology, 1976
- Water regulation by a presumptive hormone contained in identified neurosecretory cell R15 of Aplysia.The Journal of general physiology, 1976
- NEUROSECRETORY CELL PROTEIN METABOLISM IN THE LAND SNAIL,OTALA LACTEAJournal of Neurochemistry, 1976
- Requirements for bursting pacemaker potential activity in molluscan neuronesNature, 1975
- Peptide Regulation of Bursting Pacemaker Activity in a Molluscan Neurosecretory CellScience, 1974
- Analogs of cyclic AMP and cyclic GMP: General methods of synthesis and the relationship of structure to enzymic activityLife Sciences, 1974
- Cyclic AMP and amine effects on phosphorylation of specific protein in abdominal ganglion ofAplysia californica; localization and kinetic analysisJournal of Neurobiology, 1974