Adaptation to multiple electrostimulation limits hemorrhages in the brain of rats with audiogenic epilepsy

Abstract

Exposure of Krushinsky-Molodkina rats (a strain genetically predisposed to audiogenic epilepsy) to multiple electrostimulation (a course consisting of 10 sessions) prolongs the latency of epileptic seizures, lowers blood levels of stress hormones, lessens the severity of seizures, and reduces by half the area occupied by subdural hemorrhages. It is concluded that the major role in the mechanism of these protective effects is played by adaptation to stress, accompanied by the accumulation in the brain of heat-shock proteins that stabilize cellular structures.Key Words: electrostimulation; hemorrhage; audiogenic epilepsy Adaptation to stress has been shown to increase the resistance of animals not only to stressinduced injuries but also to cardiac fibrillation, acute ischemia, and myocardial infarction and to sharply reduce mortality among animals with sublethal hypoxia [6,9]. Similar results have been obtained with "mild" electrostirnulation (ES), which adapts the animals to stress [7,8]. The influence of preadaptation to multiple ES on the seventy of audiogenic epilepsy and of the brain hemorrhages associated with it [3,10], has not been investigated. However, a loud noise, which induces convulsive seizures in Krushinsky-Molodkina (KM) rats (a strain geneticaUy predisposed to audiogenic epilepsy), is certairdy an agent of stress, and adaptation of these rats to short-term stressors such as multiple ES may therefore be expected to make them more resistant to audiogenic epilepsy. The purpose of this work on KM rats was to evaluate how adaptation to short-term stress agents (multiple ES) might influence the severity of epileptic seizures, the extent of hemorrhages, ATP levels in the brain, and the magnitude of the stress reaction accompanying convulsions in these rats. MATERIALS AND METHODSA total of 39 male KM rats genetically prone to audiogenic epilepsy were used, divided into 4 groups: group 1 comprised 8 intact rats and group 2, 11 rats exposed to sound in order to elicit convulsions. Groups 3 and 4 included 20 rats that were subjected to transauricular ES daily for 10 days, after which audiogenic epilepsy was induced in 12 of these rats.For ES, standard needles for facial acupuncture were introduced into a particular point on the auricular concha of each ear. The needles were then connected to a Lasper CS-504 electrostimulator (Japan). A course of ES consisted of 10 sessions each lasting 10 rain on the first day and 20 min on the following nine days. ES was carried

Reactivity of the basilar artery in Krushinsky-Molodkina rats 24 hours after an audiogenic epileptic seizure

“…ET-1, unlike 5-HT, cannot be washed off a smooth muscle after its strong and prolonged contraction. Such strong contraction is apparently of the same type as the rigid contraction of skeletal muscle and requires very little ATP [5], whose stores in the brain after an epileptic seizure are drastically depleted [2]. That ET-1 is involved in the development of vasospasm is confirmed by the recorded elevation of protein kinase C activity in brain arteries after SAH [11].…”

“…Alternate exposure of KM rats, at 15-min intervals, to strong and weak acoustic stimuli according to a specially devised scheme resulted not only in convulsive seizures but also in subarachnoid hemorrhage (SAH) [1,2]. All tests in this study were performed with isolated basilar arteries from Wistar rats (group 1), intact KM rats (group 2), and KM rats that had developed, 24 h before the tests, an epileptiform seizure and an acute impairment of blood-brain barrier permeability accompanied by SAH (group 3).…”

“…Wistar rats and rats of the Krushinsky-Molodkina (KM) strain genetically predisposed to respond to strong acoustic stimulation by generalized convulsions [1,2] were used. Alternate exposure of KM rats, at 15-min intervals, to strong and weak acoustic stimuli according to a specially devised scheme resulted not only in convulsive seizures but also in subarachnoid hemorrhage (SAH) [1,2].…”

“…Botanical preparations (BP), complex naturally occurring compounds, have recently found wide application as adaptogens producing a complex effect on the organism's resistance to various damaging factors [1,2,11]. However, the mechanisms of their influence on resistance to stress are unclear.…”