Differential modulation of carbachol and trans-ACPD-stimulated phosphoinositide turnover following traumatic brain injury.

Abstract

In the fluid percussion model of traumatic brain injury (TBI), we examined muscarinic and metabotropic glutamate receptor-stimulated polyphosphoinositide (PPI) turnover in rat hippocampus. Moderate injury was obtained by displacement and deformation of the brain within the closed cranial cavity using a fluid percussion device. Carbachol and (+/-)-1-Aminocyclopentane-trans-1,3-dicarboxylic acid (trans-ACPD)-stimulated PPI hydrolysis was assayed in hippocampus from injured and sham-injured controls at both 1 hour and 15 days following injury. At 1 hour after TBI, the response to carbachol was enhanced in injured rats by up to 200% but the response to trans-ACPD was diminished by as much as 28%. By contrast, at 15 days after TBI, the response to carbachol was enhanced by 25% and the response to trans-ACPD was enhanced by 73%. The ionotropic glutamate agonists N-methyl-D-aspartate (NMDA), and alpha-amino-3 hydroxy-5-methyl-4-isoxazolepropionate (AMPA), did not increase PPI hydrolysis in either sham or injured rats and injury did not alter basal hydrolysis. Thus, hippocampal muscarinic and metabotropic receptors linked to phospholipase C are differentially altered by TBI.

• Authors: T M Delahunty, J Y Jiang, R T Black, B G Lyeth
• Journal: Neurochemical research (Neurochem Res) Vol. 20 Issue 4 Pg. 405-11 (Apr 1995) ISSN: 0364-3190 [Print] United States
• PMID: 7651577 (Publication Type: Comparative Study, Journal Article, Research Support, U.S. Gov't, P.H.S.)

Chemical References

• Neurotoxins
• Phosphatidylinositols
• Cycloleucine
• 1-amino-1,3-dicarboxycyclopentane
• Carbachol

Topics

• Animals
• Brain Injuries (metabolism)
• Carbachol (pharmacology)
• Cycloleucine (analogs & derivatives, pharmacology)
• Male
• Neurotoxins (pharmacology)
• Phosphatidylinositols (metabolism)
• Rats
• Rats, Sprague-Dawley
• Stimulation, Chemical