Biophysical Society Conference | Estes Park 2023

Membrane Budding and Fusion

Monday Speaker Abstracts

SIGNALING NETWORKS COUPLING CALCIUM TO SECRETION IN THE ADRENAL MEDULLA

Arun Anantharam 1 ; 1 University of Toledo, Neurosciences, Toledo, OH, USA

The adrenomedullary chromaffin cell is an important effector of the autonomic nervous system in the periphery. It responds to sympathetic stimulation by releasing hormones—including the catecholamines, epinephrine and norepinephrine—into the circulation. The sympathetic, “splanchnic” fibers that innervate chromaffin cells house a variety of peptide neurotransmitters which are thought to be co-released with acetylcholine onto the adrenal medulla. However, unlike the case with acetylcholine, the effects of peptidergic stimulation on catecholamine release remain poorly understood. The focus of this talk is on a particular peptide neurotransmitter – pituitary adenylate cyclase activating polypeptide (PACAP) – which has recently emerged as a “stress transmitter” at the splanchnic-chromaffin cell synapse. Here, the intracellular mechanisms that underlie the effects of PACAP on chromaffin cell secretion will be discussed. A model, buttressed by imaging, electrophysiological, and pharmacological data, is proposed, wherein PACAP, through a cascade of effectors, drives secretion. A key hub in this effector network is a phospholipase C epsilon (PLCe) protein, without which neither increases in intracellular calcium, nor secretion, are observed. Overall, the talk will provide new molecular insights on how peptide signals are transduced into adrenomedullary outputs, especially during the stress response.

NEGATIVE REGULATION OF EXOCYTOSIS BY AMISYN Ira Milosevic 1,2 ; 1 University of Oxford , Nuffield Department of Medicine, Oxford, United Kingdom 2 Multidisciplinary Institute for Ageing, Coimbra, Portugal No Abstract

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