Journal article
Alpha-adrenergic regulation of cholinergic responses in rat parotid acinar cells
Molecular pharmacology, Vol.18(3), pp.356-361
11/1980
DOI: 10.1016/S0026-895X(25)14510-0
PMID: 6258046
Abstract
α-Adrenergic or muscarinic cholinergic stimulation leads to a release of K+ from dispersed parotid acinar cells. Cells exposed to (-)-epinephrine at physiological pH in Hepes medium and then washed become refractory or densensitized to subsequent α-adrenergic challenge with (-)-epinephrine and to cholinergic challenge with carbachol. This α-adrenergic-elicited attenuation of the cholinergic response appears to result from a decrease in Ca2+ entry during cholinergic challenge since A23187 incubation releases as much K+ in desensitized cells as in washed controls. This desensitization occurs during (-)-epinephrine preincubation in the absence of Ca2+ and without K+ release. It is prevented if phentolamine is present. The desensitization is rapid, being complete in 2 min. Desensitization is partly reversible by incubation in fresh buffer or in the presence of phentolamine; it is completely and rapidly reversed by exposure to a high-K+ medium. Although the cholinergic response is attenuated after α-adrenergic stimulation, the binding of [3H]quinuclidinyl benzilate is the same in these cells as in washed controls. These data suggest that the attenuated cholinergic response in α-adrenergic desensitized cells results from an alteration between cholinergic receptor occupation and Ca2+ entry. This type of α-adrenergic desensitization differs from a type described previously in these cells at lower pH in Hanks’ medium. Although both types may take place at physiological pH levels, this α-adrenergic regulation of the cholinergic response is clearly an important cellular response to persistent stimulation. Since other tissues and presynaptic nerve terminals appears to have α-adrenergic and muscarinic cholinergic receptors, this regulation may be an important mechanism of adaptation to continued neuronal activity.
Details
- Title: Subtitle
- Alpha-adrenergic regulation of cholinergic responses in rat parotid acinar cells
- Creators
- James N DavisEdward OlenderWendy MauryRobert McDaniel
- Resource Type
- Journal article
- Publication Details
- Molecular pharmacology, Vol.18(3), pp.356-361
- DOI
- 10.1016/S0026-895X(25)14510-0
- PMID
- 6258046
- ISSN
- 0026-895X
- eISSN
- 1521-0111
- Grant note
- NIH NS 06233 / NINDS NIH HHS
- Language
- English
- Date published
- 11/1980
- Academic Unit
- Microbiology and Immunology
- Record Identifier
- 9984083252302771
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