Date:

2025-04-30

Title of Paper:

Sympathetic Neurogenic Ca2+ Signaling in Arteries: ATP, Noradrenaline and NPY

Journal:

Exp Physiol

Summary:

The sympathetic nervous system (SNS) plays an essential role in the control of total peripheral vascular resistance by controlling the contraction of small arteries. The SNS also exerts long-term trophic influences in health and disease; SNS hyperactivity accompanies most forms of human essential hypertension, obesity, and heart failure. At their junctions with smooth muscle cells, the peri-arterial sympathetic nerves release ATP, noradrenaline (NA) and neuropeptide Y (NPY) onto smooth muscle cells. Confocal Ca(2+) imaging studies reveal that ATP and NA each produce unique types of post-junctional Ca(2+) signals, and consequent smooth muscle cell contractions. Neurally released ATP activates post-junctional P2X1 receptors to produce local, non-propagating Ca(2+) transients, termed 'junctional Ca(2+) transients'or jCaTs. Neurally released NA binds to alpha1-adrenoceptors and can activate Ca(2+) waves or more uniform global changes in [Ca(2+)]. Neurally released NPY does not appear to produce Ca(2+) transients directly, but significantly modulates NA-induced Ca(2+) signaling. The neural release of ATP and NA, as judged by post-junctional Ca(2+) signals, electrical recording of excitatory junction potentials (EJPs), and carbon fiber amperometry to measure NA, varies markedly with the pattern of nerve activity. This probably reflects both pre- and post-junctional mechanisms, which are not yet fully understood. These phenomena, together with different temporal patterns of sympathetic nerve activity in different regional circulations, are probably an important mechanistic basis of the important selective regulation of regional vascular resistance and blood flow by the sympathetic nervous system.

Co-author:

Wier WG, Zang WJ, Lamont C, Raina H

Translation or Not:

No

Date of Publication:

2009-02-19