Differential Postmortem Delay Effect on Agonist-Mediated Phospholipase Cβ Activity in Human Cortical Crude and Synaptosomal Brain Membranes

• Published in: Neurochemical research Vol. 29; no. 7; pp. 1461 - 1465
• Main Authors: Garro, M. Asier, López de Jesús, Maider, Ruíz de Azúa, Iñigo, Callado, Luis F., Meana, J. Javier, Sallés, Joan
• Format: Journal Article
• Language: English
• Published: 01.07.2004
• ISSN: 0364-3190
• DOI: 10.1023/B:NERE.0000026412.66508.14

The phosphoinositide signal transduction system, and particularly, phospholipase C beta isozymes, are relevant in the etiopathogeny of human neuropsychiatric pathologies such as depression. Stimulation of phospholipase C beta 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 C beta activity was determined by measuring the hydrolysis of exogenous [ super(3)H]-phosphatidylinositol 4,5-bisphosphate. There was a postmortem delay-mediated decrease in the PIP sub(2) 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 PLC beta activity induced by agonist-mediated activation between crude and synaptosomal membrane preparations. These results show that the postsynaptic component of the PLC beta activity is more sensible to the postmortem delay effect.