Agonist‐Induced Phosphoinositide Hydrolysis in Choroid Plexus
- 12 December 1986
- journal article
- research article
- Published by Wiley in Journal of Neurochemistry
- Vol. 47 (6) , 1754-1760
- https://doi.org/10.1111/j.1471-4159.1986.tb13085.x
Abstract
5-Hydroxytryptamine (5-HT, serotonin) stimulates phosphoinositide hydrolysis in choroid plexus by interacting with the 5-HTlc site. In the present study, the effects of 5-HT were compared with those of other agonists. 5-HT stimulates a rapid release of all three inositol sugars in a mianserin-sensitive manner. Inositol bisphosphate and inositol trisphosphate levels increase about twofold within 2.5 min, whereas inositol monophosphate levels are not appreciably elevated until 5 min. In contrast, glutamate, carbachol, histamine, substance P, and vasopressin, agents that increase phosphoinositide hydrolysis in other tissues, do not stimulate this response in choroid plexus. High concentrations of norepinephrine increase inositol phosphate release in choroid plexus, but this effect is apparently mediated by activation of the 5-HTlc site. The depolarizing agents KCl and veratrine also fail to stimulate phosphoinositide hydrolysis in choroid plexus. These results, combined with the finding that the phosphoinositide response to 5-HT is insensitive to tetrodotoxin, suggest that the effects of 5-HT are not secondary to neurotransmitter release. Furthermore, an indirect effect mediated via arachidonic acid metabolism is unlikely, since inhibitors of cyclooxygenase and lipoxygenase do not reduce the 5-HT response. We conclude, therefore, that phosphoinositide hydrolysis is the transducing mechanism of the 5-HT 5-HTlc receptor and that the choroid plexus will serve as a useful model system for studies of this receptor.Keywords
This publication has 44 references indexed in Scilit:
- Biochemical characterization of serotonin stimulated phosphoinositide turnoverLife Sciences, 1986
- Accumulation of Pantothenic Acid by the Isolated Choroid Plexus and Brain Slices In VitroJournal of Neurochemistry, 1984
- Histamine Stimulation of Inositol 1‐Phosphate Accumulation in Lithium‐Treated Slices from Regions of Guinea Pig BrainJournal of Neurochemistry, 1984
- Muscarinic stimulation of phospholipid turnover in dissociated avian salt gland cellsFEBS Letters, 1983
- Sympathetic influence on transport functions in the choroid plexus of rabbit and ratBrain Research, 1981
- Role of phosphatidylinositol turnover in alpha1 and of adenylate cyclase inhibition in alpha2 effects of catecholaminesLife Sciences, 1980
- Barrier mechanisms for neurotransmitter monoamines in the choroid plexusActa Physiologica Scandinavica, 1980
- Sympathetic Nervous Control of Cerebrospinal Fluid Production from the Choroid PlexusScience, 1978
- Cerebrospinal Fluid Production: Stimulation by Cholera ToxinScience, 1977