Search

We have been examining the role of protein synthesis in the development and maintenance of spontaneous bursting in the rat hippocampal slice. We used stimulus train induced bursting (STIB) as an in vitro model for epileptogenesis, to study the effects of 3 different protein synthesis inhibitors (cycloheximide, anisomycin, puromycin) on the development of bursting. We report here that none of these inhibitors blocked the induction of bursting, suggesting that protein synthesis is not essential for the development of electrically induced bursting. However, when established spontaneous bursting was examined in the presence of cycloheximide, the duration of the bursting phase was markedly reduced, suggesting that the maintenance of spontaneous bursting in the early hours requires ongoing protein synthesis.

Electroconvulsive shock-induced seizures elevate seizure thresholds in humans and interfere with kindling in animals; opioids may mediate the anticonvulsant mechanism. In a potential model of acute electroconvulsive shock in hippocampal slices, a high-intensity tetanus via the mossy fibers substantially delayed subsequent in vitro kindling through the Schaffer collaterals. Naloxone blocked this effect, implicating the opioid system in the antiepileptogenic properties of this model.

The relationship between auditory stimulus rate and level of [14C]2-deoxyglucose (2-DG) uptake was examined using the 2-DG technique developed by Sokoloff as an indication of glucose uptake and neural activity. Conscious restrained albino rabbits were given one monaural tone either once per second or once per minute for 45 min, or served as unstimulated controls. Autoradiographs of the inferior colliculi from these animals were compared densitometrically. It was found that the rabbits stimulated once per second had markedly elevated levels of 2-DG uptake compared to both other groups: the rabbits stimulated once per minute and to unstimulated control rabbits. In addition, the inferior colliculus autoradiographs of the rabbits stimulated with pure tones showed a distinctive banding pattern in central nucleus different from that seen in control rabbits.

The iontophoretic injection of Ca2+ ions into voltage-clamped, silent neurons of Aplysia californica results in a prolonged, triphasic current response. This response consists of: a tetraethylammonium-sensitive outward current during the injection; followed by an inward current 10-30 s after the end of the injection; and finally a long, slowly increasing outward current that lasts for several minutes before returning to baseline.