RESUMO
Transcriptome data revealed α1 adrenoceptors (ARs) expression in platelet-derived growth factor receptor α+ cells (PDGFRα+ cells) in murine colonic musculature. The role of PDGFRα+ cells in sympathetic neural regulation of murine colonic motility was investigated. Norepinephrine (NE), via α1A ARs, activated a small conductance Ca2+ -activated K+ (SK) conductance, evoked outward currents and hyperpolarized PDGFRα+ cells (the α1A AR-SK channel signal pathway). α1 AR agonists increased intracellular Ca2+ transients in PDGFRα+ cells and inhibited spontaneous phasic contractions (SPCs) of colonic muscle through activation of a SK conductance. Sympathetic nerve stimulation inhibited both contractions of distal colon and propulsive contractions represented by the colonic migrating motor complexes (CMMCs) via the α1A AR-SK channel signal pathway. Postsynaptic signaling through α1A ARs in PDGFRα+ cells is a novel mechanism that conveys part of stress responses in the colon. PDGFRα+ cells appear to be a primary effector of sympathetic neural regulation of murine colonic motility.
