Adaptive remodeling of rat adrenomedullary stimulus-secretion coupling in a chronic hypertensive environment.

Chronic elevated blood pressure impinges on the functioning of multiple organs and therefore harms body homeostasis. Elucidating the protective mechanisms whereby the organism copes with sustained or repetitive blood pressure rises is therefore a topical challenge. Here we address this issue in the adrenal medulla, the master neuroendocrine tissue involved in the secretion of catecholamines, influential hormones in blood pressure regulation.

Adaptive remodeling of the stimulus-secretion coupling: Lessons from the 'stressed' adrenal medulla.

Stress is part of our daily lives and good health in the modern world is offset by unhealthy lifestyle factors, including the deleterious consequences of stress and associated pathologies. Repeated and/or prolonged stress may disrupt the body homeostasis and thus threatens our lives. Adaptive processes that allow the organism to adapt to new environmental conditions and maintain its homeostasis are therefore crucial.

New insights into the physiology and pathophysiology of the atypical sodium leak channel NALCN.

Cell excitability and its modulation by hormones and neurotransmitters involve the concerted action of a large repertoire of membrane proteins, especially ion channels. Unique complements of coexpressed ion channels are exquisitely balanced against each other in different excitable cell types, establishing distinct electrical properties that are tailored for diverse physiological contributions, and dysfunction of any component may induce a disease state. A crucial parameter controlling cell excitability is the resting membrane potential (RMP) set by extra- and intracellular concentrations of ions, mainly Na, K, and Cl, and their passive permeation across the cell membrane through leak ion channels.

Recording of Chromaffin Cell Electrical Activity In Situ in Acute Adrenal Slices.

Because catecholamines secretion mainly relies on the excitable nature of adrenal chromaffin cells, monitoring their electrical activity is an essential step in assessing the adrenal medullary tissue function. The difficult access to the gland in vivo allows only population activity to be recorded in this condition. In vitro preparations allow recordings of spontaneous or evoked activity from single or multiple cells, depending on the biological samples used (dissociated chromaffin cells versus adrenal tissue preparations).