Search for the structures initiating seizures triggered by intraventricular injection of the mu opioid agonist dermorphin in rats.
Free-moving rats received intraventricular (i.c.v.) or intravenous (i.v.) injections of the mu opioid agonist dermorphin (DRM). The EEG activity of the cortex and of several structures near the injected lateral ventricle was recorded. The intravenous injections of DRM did not induce epileptiform activity. The intracerebroventricular injections of DRM triggered several types of electrical seizures and interictal spikes. With the aim of determining which structure gave rise to the epileptiform discharges, we compared the time relationships of epileptiform phenomena occurring in different structures. Epileptiform discharges, at once generalized, appeared first in the CA3 area of the ventral hippocampus, with involvement of the CA1 area of ventral hippocampus, the entorhinal cortex and the amygdala following immediately. We conclude that, after intracerebroventricular injection of a mu opiate agonist, epileptiform activity originates in the CA3 area of the ventral hippocampus.
Gioanni
Y
Y
INSERM, Centre Paul Broca, Paris, France.
Greco
B
B
Prevost
J
J
D000701:Analgesics, Opioid / Q000008:administration & dosage; D000818:Animals; D001921:Brain / Q000503:physiopathology*; D004567:Electrodes, Implanted; D004569:Electroencephalography; D004827:Epilepsy / Q000139:chemically induced* / Q000503:physiopathology*; D006624:Hippocampus / Q000503:physiopathology*; D007275:Injections, Intravenous; D007276:Injections, Intraventricular; D009842:Oligopeptides / Q000008:administration & dosage; D018847:Opioid Peptides; D051381:Rats; D017207:Rats, Sprague-Dawley
D000701:Analgesics, Opioid; D009842:Oligopeptides; D018847:Opioid Peptides; C030058:dermorphin