The eccrine sweat gland, one of the major cutaneous appendages, serves primarily for thermoregulation. However, its importance in cutaneous pathophysiology has not been fully understood. The primary goal of the present proposal is to clarify the basic mechanisms of eccrine sweating at the cellular and membrane levels. Eccrine sweat secretion is the consequence of a sequence of events beginning with agonist-receptor interaction, followed by receptor-mediated membrane events (e.g., activation of G-protein, phosphatidylinositol metabolism, and calcium(Ca)-channels) and intracellular events (e.g., activation of various kinases, the cytoskeletal system, cAMP, Ca/C calmodulin systems, and intracellular pH), resulting ultimately in activation of membrane transport (e.g., activation of chloride (Cl) and potassium (K) channels, cotransporters, and parallel transporters). Previous studies indicate that activation of Cl and K channels may be of crucial importance in the activation of membrane transport during sweat secretion. Further understanding of Cl channel regulation will help solve the pathogenesis of cystic fibrosis (CF). Since the eccrine sweat gland is regulated by multiple neurotransmitters or modulators (vasoactive intestinal peptides, ATP, prostaglandins, interleukins, and cholinergic and adrenergic agonists), the regulatory role of each of these agents must be clarified. Innovative new methods for studying the regulation of membrane transport, K and Cl channels, and transporters in the sweat gland cells, namely, cell volume analysis and patch clamp methods, will be used. Interleukin 1 (IL-1) is abundantly present in human eccrine sweat and its function must be addressed. The normal function of the mouse sweat gland must be known so as to compare it with (especially CF) transgenic mice. Diagnostic guidelines and methodologies for disorders of eccrine sweating must be developed.
The specific aims of this proposal are as follows: (1) To study the regulation of ionic channels and transporters in freshly dissociated native human and rhesus eccrine clear cell using cell volume analysis; (2) to study further the regulation of K and Cl channels using patch clamp techniques during cell volume regulation, pharmacological stimulation, and intracellular application of various modulators, inhibitors, and antibodies (against various cellular components); (3) to study the function of Il-1 on ion channel activity, cytoplasmic pH, and Ca and to study regulation of IL-1 synthesis using Northern blotting and quantitative PCR techniques; (4) to study the pharmacology and function of the mouse eccrine sweat gland as a prelude to studying cystic fibrosis transgenic mice, and (5) to develop diagnostic methodologies and guidelines for clinical disorders of eccrine sweating.
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