Desensitization of A1 Adenosine Receptors
It is well known that exposure of sensitive cells to receptor agonists can cause a progressive reduction in their capacity to respond to this and related agonists. This phenomenon has been observed with cells expressing receptors from different superfamilies, and has been termed desensitization, refractoriness,tolerance, or tachyphylaxis . The mechanisms responsible for this phenomenon have been studied extensively in cells that synthesize cyclic AMP in response to beta-adrenergic agonists. Exposure of such cells to isoproterenol or similar drugs may result in receptor uncoupling, receptor sequestration, and ultimately, in downregulation of receptors, resulting in a decline in the actual number of receptors .
KeywordsAdenylyl Cyclase Adenosine Receptor cAMP Accumulation Adenylate Cyclase System Heterologous Desensitization
Unable to display preview. Download preview PDF.
- 4.Trost T, Schwabe U (1980) Adenosine receptors in fat cells. Mol Pharmacol 19:228–235.Google Scholar
- 16.Longabaugh JP, Didsbury J, Spiegel A, Stiles GL (1989) Modification of the rat adipocyte-A1 adenosine receptor-adenylate cyclase system during chronic exposure to an A1 adenosine receptor agonist-alterations in the quantity of Gsa and Gia, are not associated with changes in their m-RNAs. Mol Pharmacol 36:681–688.PubMedGoogle Scholar
- 19.Eschenhagen T, Hollmann A, Friedrichsen M, Schmitz W, Weinstein LS (1994) Regualtion of promoter activity of the human GIa-2 gene in embryonic chick cardiomyocytes. Naunyn Schmiedebergs Arch Pharmacol 349(Supplement): RI1.Google Scholar
- 22.Fredholm BB (1982) Adenosine actions and adenosine receptors after 1 week treatment with caffeine. Acta Physiol Scand 115:283–286.Google Scholar