Differential postmortem delay effect on agonist-mediated phospholipase Cbeta activity in human cortical crude and synaptosomal brain membranes.
The phosphoinositide signal transduction system, and particularly, phospholipase Cbeta isozymes, are relevant in the etiopathogeny of human neuropsychiatric pathologies such as depression. Stimulation of phospholipase Cbeta activity by muscarinic receptors and G proteins was determined in crude and synaptosomal membrane preparations from nine postmortem human frontal cortices (postmortem delay range 8 to 50 h). Thus, the phospholipase Cbeta activity was determined by measuring the hydrolysis of exogenous [3H]-phosphatidylinositol 4,5-bisphosphate. There was a postmortem delay-mediated decrease in the PIP2 hydrolysis irrespective of the membrane preparation used (P < 0.05). Moreover, there were statistically significant differences for exponential decay curve parameters (K factor and Span) of PLCbeta activity induced by agonist-mediated activation between crude and synaptosomal membrane preparations. These results show that the postsynaptic component of the PLCbeta activity is more sensible to the postmortem delay effect.
Garro
M Asier
MA
Nursing Department II, University of the Basque Country, San Sebastián/Donostia, Gipuzkoa, Spain. nfpgabem@vc.ehu.es
López de Jesús
Maider
M
Ruíz de Azúa
Iñigo
I
Callado
Luis F
LF
Meana
J Javier
JJ
Sallés
Joan
J
D000328:Adult; D001921:Brain / Q000201:enzymology* / Q000473:pathology; D002540:Cerebral Cortex / Q000201:enzymology* / Q000473:pathology; D006801:Humans; D007700:Kinetics; D008297:Male; D019269:Phosphatidylinositol 4,5-Diphosphate / Q000378:metabolism; D011180:Postmortem Changes; D011493:Protein Kinase C / Q000378:metabolism*; D064546:Protein Kinase C beta; D013574:Synaptosomes / Q000201:enzymology* / Q000473:pathology; D013997:Time Factors
D019269:Phosphatidylinositol 4,5-Diphosphate; D011493:Protein Kinase C; D064546:Protein Kinase C beta