EARLY CHANGES IN 2ND MESSENGER BUT NOT RECEPTOR-BINDING SITES AFTER ACUTE SUBDURAL-HEMATOMA - AN INVITRO AUTORADIOGRAPHIC STUDY

Neurotransmitter receptor-coupled mechanisms have been recently recogn ized as important determinants of cell damage after central nervous sy stem (CNS) trauma and ischemia. Many of these receptors exert their in tracellular effects via second messenger systems. This study used in v itro autoradiographic radioligand binding to measure beta-adrenergic a nd muscarinic cholinergic receptors and adenylate cyclase and protein kinase C (PKC) binding sites two h after acute subdural hematoma in ra ts. Both beta-adrenergic and cholinergic receptor binding sites were u nchanged in comparison to controls, while adenylate cyclase binding si gnificantly decreased in the ischemic cortex under the hematoma. These changes may constitute a major limiting factor on receptor-linked the rapeutic strategies in trauma and ischemia. Protein kinase C activatio n significantly increased in the ischemic area under the hematoma in t hese studies. This appears to be a response to calcium flux, which may be in part glutamate mediated.