Preincubation with substance P induces substance P-stimulated phosphatidylinositol turnover in cultured cerebellar astrocytes.
In this study we have investigated the effects of preincubation of cultured astrocytes with substance P (SP) on subsequent 125I-Bolton-Hunter conjugated SP (125I-BHSP) receptor binding, and SP-stimulated phosphatidyl-inositol (PI) accumulation. Spinal cord astrocytes preincubated for up to 96 h with SP (0.001-1,000 nM) suffered a dose-dependent decrease in both subsequent 125I-BHSP and SP-stimulated PI turnover. In contrast, preincubation of cerebellar astrocytes with SP resulted in an increase in SP-stimulated PI turnover, with no change in 125I-BHSP receptor binding. SP-induced PI turnover in cerebellar astrocytes was maximal after 72 h of preincubation with 0.1 nM SP. These data suggest that increased coupling between receptor and second messenger occurs in response to chronic exposure to SP.
Marriott
D R
DR
Department of Biochemistry, Imperial College of Science, Technology and Medicine, London, England.
Wilkin
G P
GP
D000818:Animals; D001253:Astrocytes / Q000166:cytology* / Q000378:metabolism* / Q000648:ultrastructure; D002478:Cells, Cultured; D002531:Cerebellum / Q000166:cytology* / Q000378:metabolism / Q000648:ultrastructure; D004305:Dose-Response Relationship, Drug; D007457:Iodine Radioisotopes; D010716:Phosphatidylinositols / Q000378:metabolism*; D051381:Rats; D018040:Receptors, Neurokinin-1; D017981:Receptors, Neurotransmitter / Q000032:analysis / Q000378:metabolism; D013373:Substance P / Q000378:metabolism / Q000494:pharmacology*; D013936:Thymidine / Q000378:metabolism; D013997:Time Factors; D014316:Tritium
D007457:Iodine Radioisotopes; D010716:Phosphatidylinositols; D018040:Receptors, Neurokinin-1; D017981:Receptors, Neurotransmitter; D014316:Tritium; D013373:Substance P; D013936:Thymidine