ECoG spectral analysis of apamin effects on the rat brain with pretrigeminal or high spinal transection of the central nervous system.
Rats were injected into one lateral ventricle (icv) with apamin (50 and 100 ng per animal). The resulting desynchronization pattern in the electro-corticogram (ECoG) and the symptoms of apaminism (uncoordinated hypermotility and jerks) were monitored. The results of presented experiments contributed additional data concerning the topography of apamin effects. When injected into the ventricle of intact rats, generalized apaminism and massive desynchronization (reduction of total power and increase in beta waves band) of the cortical ECoG emerged. Transection of the spinal cord at the C1-C2 level (encéphalé isolé preparation) displayed apaminism of the head together with significant decrease in the total and relative power connected with a significant decrease in both beta and theta waves. Pretrigeminal transsection of the brain stem abolished the desynchronization in ECoG, whereas the generalized apaminism persisted, however it occurred after a longer latency than in intact animals. Morphine (10 mg/kg, sc) reversed the ECoG effects of apamin in intact rats but remained without effect on the motility changes. Our data indicate that apamin acts primarily on the brain stem and spinal cord, i.e. the structures possessing a sensory input, and by that way indirectly on the higher integrating systems.
Janicki
J K
JK
Department of Pharmacology, Institute of Physiological Sciences, Medical Academy, Warszawa, Poland.
Krzaścik
P
P
Paulo
E A
EA
Mészáros
J
J
Szreniawski
Z
Z
D000758:Anesthesia; D000818:Animals; D001030:Apamin / Q000494:pharmacology*; D001514:Bee Venoms / Q000494:pharmacology*; D001921:Brain / Q000187:drug effects*; D003655:Decerebrate State; D004569:Electroencephalography; D007276:Injections, Intraventricular; D008297:Male; D009046:Motor Neurons / Q000187:drug effects; D051381:Rats; D011919:Rats, Inbred Strains; D013116:Spinal Cord / Q000502:physiology; D014276:Trigeminal Nerve / Q000502:physiology
D001514:Bee Venoms; D001030:Apamin