title: Cyclic GMP formation and inositol phosphate accumulation do not share common origins in rat brain slices.
abstract: Cyclic GMP formation and inositol phospholipid hydrolysis were studied in rat brain slices to determine if the two processes have common origins. Muscarinic cholinergic stimulation enhanced [3H]inositol phosphate ([ 3H]IP) accumulation from slices prelabelled with [3H]inositol but did not affect cyclic GMP formation in the cortex, striatum, or cerebellum. An elevated level of extracellular K+ stimulated accumulation of both cyclic GMP and [3H]IP in cortex slices. The former, but not the latter, was reduced by lipoxygenase and phospholipase A2 inhibition. Calcium channel activation enhanced and blockade reduced K+-stimulated [3H]IP formation without affecting the cyclic GMP level, and there were differences in the Ca2+ requirements for the two responses. Thus, there is no support for the concept that guanylate cyclase activation inevitably accompanies inositol phospholipid breakdown, and the evidence presented demonstrates that K+ stimulation promotes cyclic GMP and [3H]IP accumulation by different transducing pathways.
mesh_terms: D015056:1-Methyl-3-isobutylxanthine / Q000494:pharmacology; D001498:3-Pyridinecarboxylic acid, 1,4-dihydro-2,6-dimethyl-5-nitro-4-(2-(trifluoromethyl)phenyl)-, Methyl ester / Q000494:pharmacology; D000818:Animals; D001921:Brain / Q000378:metabolism*; D002451:Cell Compartmentation; D006152:Cyclic GMP / Q000096:biosynthesis*; D007295:Inositol Phosphates / Q000378:metabolism*; D017275:Isradipine; D008297:Male; D010069:Oxadiazoles / Q000494:pharmacology; D011188:Potassium / Q000378:metabolism; D051381:Rats; D011919:Rats, Inbred Strains; D013403:Sugar Phosphates / Q000378:metabolism*; D010738:Type C Phospholipases / Q000378:metabolism
chemical_list: D007295:Inositol Phosphates; D010069:Oxadiazoles; D013403:Sugar Phosphates; D001498:3-Pyridinecarboxylic acid, 1,4-dihydro-2,6-dimethyl-5-nitro-4-(2-(trifluoromethyl)phenyl)-, Methyl ester; D010738:Type C Phospholipases; D006152:Cyclic GMP; D011188:Potassium; D015056:1-Methyl-3-isobutylxanthine; D017275:Isradipine