IFIBYNE   05513
INSTITUTO DE FISIOLOGIA, BIOLOGIA MOLECULAR Y NEUROCIENCIAS
Unidad Ejecutora - UE
congresos y reuniones científicas
Título:
Rapid Endocytosis in mouse chromaffin cells is regulated by intracellular calcium sources
Autor/es:
ANA VERÓNICA BELINGHERI; FERNANDO D. MARENGO
Lugar:
Huerta Grande (C¡§®rdoba)
Reunión:
Congreso; Reuni¡§®n Anual de la Sociedad Argentina de Investigaci¡§®n en Neurociencia; 2011
Institución organizadora:
Sociedad Argentina de Investigaci¡§®n en Neurociencia
Resumen:
Endocytosis is critical for maintaining membrane homeostasis and secretion reliability in neuroendocrine cells and neurons. Chromaffin cell rapid endocytosis (RE) is a Ca2+ dependent process, which can overcome the previous exocytosis if the Ca2+ entry is ¡Ý 75pC (excess retrieval, EX). In order to study if intracellular Ca2+ sources may regulate RE, we performed patch clamp capacitance measurements and applied specific pharmacological agents. The global participation of Ca2+ release from endoplasmic reticulum (Er) was studied by depleting this organelle with thapsigargin+caffeine pretreatment, and the specific contribution of ryanodine receptors was studied by ryanodine application. We observed similar effects with both treatments (a reduction of RE by 40 and 60% respectively). We next studied the participation of Ca2+ release through IP3 receptors (IP3R). On one hand, IP3R inhibition with 2-APB, partially reduced RE (by 50%), blocked EX and made the kinetic slower. But on the other hand, heparin, a more specific IP3R blocker, did not mimick those effects. This could be explained by the reported inhibitory effect of 2-APB over the SERCA, what would reduce the Er Ca2+ content. These results together suggest that RE is regulated by Ca2+ release through ryanodine receptors.