Effects of histamine on phosphoinositide metabolism in chick cerebral cortex.
Effects of histamine (HA) and agonists of HA receptors on phosphoinositide metabolism in chick cerebral cortex have been studied using two approaches - measurement of inositol 1,4,5-trisphosphate (IP3) level by a specific and sensitive IP3 receptor radioassay, and analysis of [3H]inositol phosphates accumulation in cortical slices prelabeled with myo-[3H]inositol. HA concentration-dependently elevated IP3 levels in slices of chick cerebral cortex. The effect of HA was mimicked by 2-methylHA, a selective agonist of H1-HA receptors, and blocked by mepyramine, an H1 receptor antagonist. 4-MethylHA and Ralpha-methylHA, selective agonists of H2- and H3-HA receptors, respectively, did not affect IP3 level in the chick cerebrum. In cerebral cortical slices prelabeled with myo-[3H]inositol, 2-methylHA significantly stimulated [3H]inositol phosphates accumulation, whereas HA only slightly and non-significantly increased phosphoinositide metabolism. It is suggested that phospholipase C-coupled H1-HA receptors are present in the chick cerebral cortex, yet their number seems to be a small one.
Zawilsk
J B
JB
Department of Biogenic Amines, Polish Academy of Sciences, Lódź.
Woldan-Tambor
A
A
Kubal
K
K
Nowak
Z
Z
D000818:Animals; D002540:Cerebral Cortex / Q000187:drug effects / Q000378:metabolism*; D002645:Chickens; D006632:Histamine / Q000494:pharmacology*; D006634:Histamine H1 Antagonists / Q000494:pharmacology; D066298:In Vitro Techniques; D015544:Inositol 1,4,5-Trisphosphate / Q000378:metabolism; D007295:Inositol Phosphates / Q000378:metabolism*; D008297:Male; D011738:Pyrilamine / Q000494:pharmacology; D011869:Radioligand Assay
D006634:Histamine H1 Antagonists; D007295:Inositol Phosphates; D006632:Histamine; D015544:Inositol 1,4,5-Trisphosphate; D011738:Pyrilamine