Biomaterial Database

Effects of postsynaptic GABA(B) receptor activation on epileptiform activity in hippocampal slices. 2001

Z Q Xiong, and J L Stringer

Department of Pharmacology and Division of Neuroscience, Baylor College of Medicine, 1 Baylor Plaza, Houston, TX 77030, USA.

GABA(B) receptor agonists have been reported to have both pro- and antiepileptic properties. Here, the effects of a GABA(B) receptor agonist, baclofen, were studied on epileptiform activity induced in the absence of synaptic transmission - to focus on the postsynaptic effects. Perfusion of hippocampal slices with 0-added calcium and high potassium induced field bursts in CA1 and the dentate gyrus. Addition of baclofen caused a transient suppression of the field bursts in CA1 and the dentate gyrus. The duration of the suppression was dependent on the concentration of baclofen and when the bursts reappeared they had a larger amplitude than before baclofen. Baclofen also suppressed the multiple population spikes evoked by antidromic stimulation in the dentate gyrus. This effect also decreased with continued baclofen perfusion. The effects of baclofen on the amplitude of the spontaneous field bursts and on the stimulation-induced multiple population spikes were blocked by the GABA(B) receptor antagonist SCH 50911, suggesting that these effects of baclofen are mediated by GABA(B) receptor activation. Baclofen significantly increased the peak extracellular K(+) concentration during each field burst in the dentate gyrus but did not change the baseline level of K(+) between field bursts. The results suggest that postsynaptic GABA(B) receptor activation by baclofen has transient antiepileptic effects followed by a rebound increase in excitability.

UI	MeSH Term	Description	Entries
D008297	Male		Males
D011188	Potassium	An element in the alkali group of metals with an atomic symbol K, atomic number 19, and atomic weight 39.10. It is the chief cation in the intracellular fluid of muscle and other cells. Potassium ion is a strong electrolyte that plays a significant role in the regulation of fluid volume and maintenance of the WATER-ELECTROLYTE BALANCE.
D004567	Electrodes, Implanted	Surgically placed electric conductors through which ELECTRIC STIMULATION is delivered to or electrical activity is recorded from a specific point inside the body.	Implantable Electrodes,Implantable Stimulation Electrodes,Implanted Electrodes,Implanted Stimulation Electrodes,Electrode, Implantable,Electrode, Implantable Stimulation,Electrode, Implanted,Electrode, Implanted Stimulation,Electrodes, Implantable,Electrodes, Implantable Stimulation,Electrodes, Implanted Stimulation,Implantable Electrode,Implantable Stimulation Electrode,Implanted Electrode,Implanted Stimulation Electrode,Stimulation Electrode, Implantable,Stimulation Electrode, Implanted,Stimulation Electrodes, Implantable,Stimulation Electrodes, Implanted
D004827	Epilepsy	A disorder characterized by recurrent episodes of paroxysmal brain dysfunction due to a sudden, disorderly, and excessive neuronal discharge. Epilepsy classification systems are generally based upon: (1) clinical features of the seizure episodes (e.g., motor seizure), (2) etiology (e.g., post-traumatic), (3) anatomic site of seizure origin (e.g., frontal lobe seizure), (4) tendency to spread to other structures in the brain, and (5) temporal patterns (e.g., nocturnal epilepsy). (From Adams et al., Principles of Neurology, 6th ed, p313)	Aura,Awakening Epilepsy,Seizure Disorder,Epilepsy, Cryptogenic,Auras,Cryptogenic Epilepsies,Cryptogenic Epilepsy,Epilepsies,Epilepsies, Cryptogenic,Epilepsy, Awakening,Seizure Disorders
D005260	Female		Females
D006624	Hippocampus	A curved elevation of GRAY MATTER extending the entire length of the floor of the TEMPORAL HORN of the LATERAL VENTRICLE (see also TEMPORAL LOBE). The hippocampus proper, subiculum, and DENTATE GYRUS constitute the hippocampal formation. Sometimes authors include the ENTORHINAL CORTEX in the hippocampal formation.	Ammon Horn,Cornu Ammonis,Hippocampal Formation,Subiculum,Ammon's Horn,Hippocampus Proper,Ammons Horn,Formation, Hippocampal,Formations, Hippocampal,Hippocampal Formations,Hippocampus Propers,Horn, Ammon,Horn, Ammon's,Proper, Hippocampus,Propers, Hippocampus,Subiculums
D000241	Adenosine	A nucleoside that is composed of ADENINE and D-RIBOSE. Adenosine or adenosine derivatives play many important biological roles in addition to being components of DNA and RNA. Adenosine itself is a neurotransmitter.	Adenocard,Adenoscan
D000818	Animals	Unicellular or multicellular, heterotrophic organisms, that have sensation and the power of voluntary movement. Under the older five kingdom paradigm, Animalia was one of the kingdoms. Under the modern three domain model, Animalia represents one of the many groups in the domain EUKARYOTA.	Animal,Metazoa,Animalia
D001418	Baclofen	A GAMMA-AMINOBUTYRIC ACID derivative that is a specific agonist of GABA-B RECEPTORS. It is used in the treatment of MUSCLE SPASTICITY, especially that due to SPINAL CORD INJURIES. Its therapeutic effects result from actions at spinal and supraspinal sites, generally the reduction of excitatory transmission.	Baclophen,Chlorophenyl GABA,Apo-Baclofen,Atrofen,Ba-34,647,Ba-34647,Baclofen AWD,Baclofène-Irex,Baclospas,CIBA-34,647-BA,Clofen,Gen-Baclofen,Genpharm,Lebic,Lioresal,Liorésal,Nu-Baclo,PCP-GABA,PMS-Baclofen,beta-(Aminomethyl)-4-chlorobenzenepropanoic Acid,beta-(p-Chlorophenyl)-gamma-aminobutyric Acid,AWD, Baclofen,Apo Baclofen,ApoBaclofen,Ba34,647,Ba34647,Baclofène Irex,BaclofèneIrex,CIBA34,647BA,GABA, Chlorophenyl,Gen Baclofen,GenBaclofen,Nu Baclo,NuBaclo,PMS Baclofen,PMSBaclofen
D013569	Synapses	Specialized junctions at which a neuron communicates with a target cell. At classical synapses, a neuron's presynaptic terminal releases a chemical transmitter stored in synaptic vesicles which diffuses across a narrow synaptic cleft and activates receptors on the postsynaptic membrane of the target cell. The target may be a dendrite, cell body, or axon of another neuron, or a specialized region of a muscle or secretory cell. Neurons may also communicate via direct electrical coupling with ELECTRICAL SYNAPSES. Several other non-synaptic chemical or electric signal transmitting processes occur via extracellular mediated interactions.	Synapse