Development of the hypersecretory phenotype in the population of adrenal chromaffin cells from prehypertensive SHRs.

The hypersecretory phenotype of adrenal chromaffin cells (CCs) from early spontaneously hypertensive rats (SHRs) mainly results from enhanced Ca-induced Ca-release (CICR). A key question is if these abnormalities can be traced to the prehypertensive stage. Spontaneous and stimulus-induced catecholamine exocytosis, intracellular Ca signals, and dense-core granule size and density were examined in CCs from prehypertensive and hypertensive SHRs and compared with age-matched Wistar-Kyoto rats (WKY).

Endophilin-A coordinates priming and fusion of neurosecretory vesicles via intersectin.

Endophilins-A are conserved endocytic adaptors with membrane curvature-sensing and -inducing properties. We show here that, independently of their role in endocytosis, endophilin-A1 and endophilin-A2 regulate exocytosis of neurosecretory vesicles. The number and distribution of neurosecretory vesicles were not changed in chromaffin cells lacking endophilin-A, yet fast capacitance and amperometry measurements revealed reduced exocytosis, smaller vesicle pools and altered fusion kinetics.

Dynamic Generation of Concentration- and Temporal-Dependent Chemical Signals in an Integrated Microfluidic Device for Single-Cell Analysis.

Intracellular signaling pathways are affected by the temporal nature of external chemical signaling molecules such as neurotransmitters or hormones. Developing high-throughput technologies to mimic these time-varying chemical signals and to analyze the response of single cells would deepen our understanding of signaling networks. In this work, we introduce a microfluidic platform to stimulate hundreds of single cells with chemical waveforms of tunable frequency and amplitude.

GABA receptor: a unique modulator of excitability, Ca signaling, and catecholamine release of rat chromaffin cells.

The role of gamma-aminobutyric acid (GABA) in adrenal medulla chromaffin cell (CC) function is just beginning to unfold. GABA is stored in catecholamine (CA)-containing dense core granules and is presumably released together with CA, ATP, and opioids in response to physiological stimuli, playing an autocrine-paracrine role on CCs. The reported paradoxical "dual action" of GABA-R activation (enhancement of CA secretion and inhibition of synaptically evoked CA release) is only one aspect of GABA's multifaceted actions.