The long term objective of this application is to gain a good understanding of the physiology and pharmacology of the function of mucus and fluid secretion in airways both in normal and disease states. Cocaine is a major drug of abuse which is taken primarily by inhalation of cocaine powder through the nose or by smoking the free-base. This means that the mucosal tissue of the nose and upper airways will be acutely exposed to high concentrations of this agent. Thus this drug either as a local anesthetic or as a sympathomimetic agent will lead to changes in the function of the submuscosal gland cells. In addition cocaine is generally taken repeatedly by those who use it. Thus, it may be that those who take it over an extended period of time may become tolerant to its action. This proposal is designed to determine the normal stimuli which induce the secretion of fluid and mucus from submuscosal gland cells. Then with this knowledge to determine what the acute and chronic effects of cocaine are on the functioning submuscosal gland cells. the properties of submuscosal gland cells isolated from weanling swine will be determined by isolating the cells from the mucosa using enzymes, followed by a purification step using density grandients. The cells will then be used in radioligand binding assays to determine the characteristics of the adrenergic and muscarinic receptors present on these cells and how these characteristics may be changed by cocaine exposure. Second the physiological function of the cells will be assayed by measuring neurotransmitter and neurally evoked mucus secretion adn chloride flux. The effect of cocaine on these functions will be determined. Finally, the effects of cocaine on the properties of ion channels in the tissue will be determined by use of the patch clamp technique. The ability of cocaine to block, or interact in other ways, with the ionic channels will be determined. The effects of chronic exposure of swine to cocaine on the function of submucosal gland cells will also be determined. Swine will be exposed via intranasal application of cocaine powder 2-3 times daily for up to 7 days. The pharmacological and physiological characteristics of gland cell function will then be determined by the methods given above. The effects of chronic cocaine exposure on submucosal gland cell function will also be examined in swine pretreated with reserpine to deplete peripheral catecholamine stores. This will permit an examination of the action of cocaine in the absence of its' sympathomimetic action.

National Institute of Health (NIH)
National Institute on Drug Abuse (NIDA)
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University of Mississippi Medical Center
Schools of Medicine
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Shieh, C C; Petrini, M F; Dwyer, T M et al. (1992) Cromakalim effects of acetylcholine-induced changes in cytosolic calcium and tension in swine trachealis. J Pharmacol Exp Ther 260:261-8
Dwyer, T M; Szebeni, A; Diveki, K et al. (1992) Transient cholinergic glycoconjugate secretion from swine tracheal submucosal gland cells. Am J Physiol 262:L418-26
Saunders, H H; Farley, J M (1992) Pharmacological properties of potassium currents in swine tracheal smooth muscle. J Pharmacol Exp Ther 260:1038-44
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Dwyer, T M; Farley, J M (1991) Intracellular chloride in submucosal gland cells. Life Sci 48:2119-27
Farley, J M; Adderholt, G; Dwyer, T M (1991) Autonomic stimulation of short circuit current in swine trachea. Life Sci 48:873-80
Farley, J M; Dwyer, T M (1991) Pirenzepine block of ACH-induced mucus secretion in tracheal submucosal gland cells. Life Sci 48:59-67