Cyclic GMP inhibits phosphoinositide turnover in choroid plexus: evidence for interactions between second messengers concurrently triggered by 5-HT2C receptors.
The present study examined the effects of the nitric oxide generator sodium nitroprusside (SNP), a membrane-permeable cGMP analog (dibutyryl-cGMP) and low calcium buffer incubation on choroid plexus serotonin 5-HT2C receptor-mediated inositol monophosphate (IP) production. SNP (100 microM) substantially inhibited 10(-6)M serotonin-stimulated IP production (-46%, P < 0.02). Serotonin-stimulated IP production was increased in low calcium buffer (+280%, P < 0.01) in which serotonin-stimulated cGMP formation is attenuated. Addition of dibutyryl-cGMP (500 microM) inhibited IP formation in low calcium buffer. The present data are suggestive of an inhibitory effect of cGMP on IP formation in choroid plexus, and raise the intriguing possibility of interactions between second messenger systems concurrently activated by 5-HT2C receptors.
Kaufman
M J
MJ
Department of Environmental Health Sciences, Johns Hopkins University, Baltimore, MD 21205, USA.
Hirata
F
F
D000818:Animals; D002118:Calcium / Q000494:pharmacology; D002831:Choroid Plexus / Q000187:drug effects* / Q000378:metabolism; D003995:Dibutyryl Cyclic GMP / Q000494:pharmacology*; D066298:In Vitro Techniques; D009599:Nitroprusside / Q000494:pharmacology*; D010716:Phosphatidylinositols / Q000378:metabolism*; D011985:Receptors, Serotonin / Q000187:drug effects*; D015290:Second Messenger Systems / Q000187:drug effects*; D013552:Swine
D010716:Phosphatidylinositols; D011985:Receptors, Serotonin; D009599:Nitroprusside; D003995:Dibutyryl Cyclic GMP; D002118:Calcium