ABSTRACT
Weak (20-50 microA) sine-wave stimulation at 60 Hz (SWS) of either the mossy fibers or the Schaffer collaterals promoted epileptiform synchronized bursts in the CA2/3 area of rat hippocampal slices in the absence of epileptogenic agents. Following brief SWSs (2-10 sec every 5 min), delayed synchronized bursts (DSBs) were triggered by weak test pulses in either pathway and transmitted to CA1. The long (2-10 sec) refractory periods which followed synchronized bursts in CA2/3 limited their rate of occurrence. Furthermore, SWS decreased the activity for several minutes in slices that exhibited frequent bursts. DSBs were reversibly blocked by perfusion with the N-methyl-D-aspartate (NMDA) specific antagonist DL-2-amino-5-phosphono-valeric acid (APV). The involvement of NMDA receptors was further suggested by the facilitation of CA2/3 synchronized bursts in medium with NMDA (5 microM) or lacking magnesium, and by iontophoresis of NMDA in the CA2/3 stratum radiatum. The findings that SWS-induced DSBs persisted for hours in undisturbed slices, and that bursts abolished by APV reappeared during washout in control solution, suggest long-term changes in the CA2/3 synaptic region.
Subject(s)
Hippocampus/physiopathology , Receptors, Neurotransmitter/physiology , Seizures/physiopathology , 2-Amino-5-phosphonovalerate , Animals , Aspartic Acid/analogs & derivatives , Aspartic Acid/pharmacology , Electric Stimulation , Hippocampus/drug effects , Hippocampus/metabolism , In Vitro Techniques , Male , N-Methylaspartate , Penicillins , Rats , Rats, Inbred Strains , Receptors, N-Methyl-D-Aspartate , Receptors, Neurotransmitter/drug effects , Seizures/chemically induced , Seizures/metabolism , Valine/analogs & derivativesABSTRACT
Acute spontaneous cerebellar hemorrhage presenting with ataxia, dysarthria, vomiting, dizziness, and coma is commonly the result of hypertension. Early diagnosis is possible, and appropriate treatment, if timely executed, may be lifesaving.
Subject(s)
Cerebellar Diseases/etiology , Hemorrhage/etiology , Hypertension/complications , Acute Disease , Adult , Aged , Cerebellar Diseases/diagnosis , Female , Hemorrhage/diagnosis , Humans , MaleABSTRACT
Rarely, a lesion simulating a colloid cyst of the third ventricle may present with obstructive hydrocephalus and headache. Experience with an arteriovenous malformation in this location is discussed.
