Inositol phospholipid hydrolysis in human brain; adenosine inhibition of the response to histamine.
1. Inositol phospholipid hydrolysis was examined in human cerebral cortex slices by a [3H]-inositol prelabelling assay. 2. Enhancement of [3H]-inositol phosphates accumulation was observed in the presence of carbachol, noradrenaline, histamine, 5-hydroxytryptamine (5-HT) and depolarizing concentrations of KCl. 3. Despite having no effect alone, adenosine (and its analogue 2-chloroadenosine) selectively inhibited the direct response to histamine. 4. The inhibition due to adenosine was antagonized by theophylline, but not by 8-cyclopropyltheophylline.
Kendall
D A
DA
Department of Physiology & Pharmacology, Queen's Medical Centre, Nottingham.
Firth
J L
JL
D015762:2-Chloroadenosine / Q000494:pharmacology; D000241:Adenosine / Q000037:antagonists & inhibitors / Q000494:pharmacology*; D000328:Adult; D000368:Aged; D001921:Brain / Q000187:drug effects / Q000378:metabolism*; D002217:Carbachol / Q000494:pharmacology; D005260:Female; D006632:Histamine / Q000494:pharmacology*; D006801:Humans; D066298:In Vitro Techniques; D007295:Inositol Phosphates / Q000378:metabolism*; D008297:Male; D008875:Middle Aged; D009638:Norepinephrine / Q000494:pharmacology; D011189:Potassium Chloride / Q000494:pharmacology; D012701:Serotonin / Q000494:pharmacology; D013806:Theophylline / Q000031:analogs & derivatives / Q000494:pharmacology
D007295:Inositol Phosphates; D015762:2-Chloroadenosine; D012701:Serotonin; C055488:8-cyclopropyltheophylline; D011189:Potassium Chloride; D006632:Histamine; D002217:Carbachol; D013806:Theophylline; D000241:Adenosine; D009638:Norepinephrine