Peptide factor extracted from molluscan ganglia that modulates bursting pacemaker activity

Abstract

NEUROHORMONES have been suggested as long term regulators of the physiology and biochemistry of nervous tissue^1–3. Long term changes in the electrophysiology and biochemistry of a specific neurosecretory cell in the land snail Otala lactea^4,5 suggested such a form of long term hormonal regulation, and in fact several vertebrate neurohypophysial peptides cause long term changes in the membrane properties of this cell⁶. The regulatory effects observed involve the induction or potentiation of bursting pacemaker potential (BPP) activity, resulting in net excitation of the cell. These effects are different from the conventional transient conductance changes produced by various putative transmitters on these cells. We have now found a naturally occurring substance present in the snail brain that produces similar long term changes in the membrane properties of this neurosecretory cell. The results provide evidence for a peptide neurohormone which may function physiologically in the seasonal regulation of the physiology and biochemistry of a neurosecretory cell.