Biomaterial Database

Actions of steroids and bemegride on the GABAA receptor of mouse spinal neurones in culture. 1990

D K Mistry, and G A Cottrell

Department of Biology and Preclinical Medicine, University of St Andrews.

The effects of a synthetic and an endogenous steroid were studied on the GABAA receptors of isolated mouse spinal neurones, maintained in culture. Low doses of alphaxalone reversibly increased GABA-evoked whole-cell currents. Alphaxalone at higher doses (10-50 microM), when pressure ejected onto spinal neurones, also directly evoked a membrane chloride current. Such currents were reversibly suppressed by bicuculline (a GABAA antagonist) and enhanced by phenobarbitone. 5 beta-Pregnan-3 alpha-ol-20-one, a progesterone metabolite, dose-dependently potentiated the amplitude of GABA-evoked whole-cell currents. The mechanism of potentiation was examined at the single-channel level using outside-out patches from spinal neurones. The main action of the steroid on the GABAA receptor appears to be similar to that found for barbiturates, in that they prolonged GABA-activated bursts of channel openings. Bemegride had an antagonistic action on the GABAA receptor, suppressing both GABA- and pentobarbitone-evoked whole-cell currents to similar extents.

UI	MeSH Term	Description	Entries
D008564	Membrane Potentials	The voltage differences across a membrane. For cellular membranes they are computed by subtracting the voltage measured outside the membrane from the voltage measured inside the membrane. They result from differences of inside versus outside concentration of potassium, sodium, chloride, and other ions across cells' or ORGANELLES membranes. For excitable cells, the resting membrane potentials range between -30 and -100 millivolts. Physical, chemical, or electrical stimuli can make a membrane potential more negative (hyperpolarization), or less negative (depolarization).	Resting Potentials,Transmembrane Potentials,Delta Psi,Resting Membrane Potential,Transmembrane Electrical Potential Difference,Transmembrane Potential Difference,Difference, Transmembrane Potential,Differences, Transmembrane Potential,Membrane Potential,Membrane Potential, Resting,Membrane Potentials, Resting,Potential Difference, Transmembrane,Potential Differences, Transmembrane,Potential, Membrane,Potential, Resting,Potential, Transmembrane,Potentials, Membrane,Potentials, Resting,Potentials, Transmembrane,Resting Membrane Potentials,Resting Potential,Transmembrane Potential,Transmembrane Potential Differences
D009474	Neurons	The basic cellular units of nervous tissue. Each neuron consists of a body, an axon, and dendrites. Their purpose is to receive, conduct, and transmit impulses in the NERVOUS SYSTEM.	Nerve Cells,Cell, Nerve,Cells, Nerve,Nerve Cell,Neuron
D011277	Pregnanediones	Pregnane derivatives in which two side-chain methyl groups or two methylene groups in the ring skeleton (or a combination thereof) have been oxidized to keto groups.	Diketopregnanes,Dioxopregnanes
D011278	Pregnanes	Saturated derivatives of the steroid pregnane. The 5-beta series includes PROGESTERONE and related hormones; the 5-alpha series includes forms generally excreted in the urine.
D011280	Pregnanolone	A pregnane found in the urine of pregnant women and sows. It has anesthetic, hypnotic, and sedative properties.	Eltanolone,3 alpha, 5 beta-Tetrahydroprogesterone,3 alpha-Hydroxy-5 alpha-pregnan-20-one,3 alpha-Hydroxy-5 beta-pregnan-20-one,3-Hydroxypregnan-20-one,3beta-Hydroxy-5alpha-pregnan-20-one,Allopregnan-3 beta-ol-20-one,Allopregnanolone,Epipregnanolone,Pregnan-3alpha-ol-20-one,Pregnanolone, (3alpha)-isomer,Pregnanolone, (3alpha, 5beta, 17-alpha)-isomer,Pregnanolone, (3alpha,5alpha)-isomer,Pregnanolone, (3alpha,5beta)-isomer,Pregnanolone, (3beta)-isomer,Pregnanolone, (3beta, 5alpha)-isomer,Pregnanolone, (3beta, 5alpha, 17alpha)-isomer,Pregnanolone, (3beta, 5alpha, 8alpha, 17beta)-isomer,Pregnanolone, (3beta, 5beta)-isomer,Pregnanolone, (3beta, 5beta, 17alpha)-isomer,Pregnanolone, (3beta, 5beta,14beta)-isomer,Pregnanolone, (5alpha)-isomer,Sepranolone,3 Hydroxypregnan 20 one,3 alpha Hydroxy 5 alpha pregnan 20 one,3 alpha Hydroxy 5 beta pregnan 20 one,3 alpha, 5 beta Tetrahydroprogesterone,3beta Hydroxy 5alpha pregnan 20 one,Allopregnan 3 beta ol 20 one,Pregnan 3alpha ol 20 one,alpha-Hydroxy-5 alpha-pregnan-20-one, 3,alpha-Hydroxy-5 beta-pregnan-20-one, 3,alpha-pregnan-20-one, 3 alpha-Hydroxy-5,beta-ol-20-one, Allopregnan-3,beta-pregnan-20-one, 3 alpha-Hydroxy-5
D011963	Receptors, GABA-A	Cell surface proteins which bind GAMMA-AMINOBUTYRIC ACID and contain an integral membrane chloride channel. Each receptor is assembled as a pentamer from a pool of at least 19 different possible subunits. The receptors belong to a superfamily that share a common CYSTEINE loop.	Benzodiazepine-Gaba Receptors,GABA-A Receptors,Receptors, Benzodiazepine,Receptors, Benzodiazepine-GABA,Receptors, Diazepam,Receptors, GABA-Benzodiazepine,Receptors, Muscimol,Benzodiazepine Receptor,Benzodiazepine Receptors,Benzodiazepine-GABA Receptor,Diazepam Receptor,Diazepam Receptors,GABA(A) Receptor,GABA-A Receptor,GABA-A Receptor alpha Subunit,GABA-A Receptor beta Subunit,GABA-A Receptor delta Subunit,GABA-A Receptor epsilon Subunit,GABA-A Receptor gamma Subunit,GABA-A Receptor rho Subunit,GABA-Benzodiazepine Receptor,GABA-Benzodiazepine Receptors,Muscimol Receptor,Muscimol Receptors,delta Subunit, GABA-A Receptor,epsilon Subunit, GABA-A Receptor,gamma-Aminobutyric Acid Subtype A Receptors,Benzodiazepine GABA Receptor,Benzodiazepine Gaba Receptors,GABA A Receptor,GABA A Receptor alpha Subunit,GABA A Receptor beta Subunit,GABA A Receptor delta Subunit,GABA A Receptor epsilon Subunit,GABA A Receptor gamma Subunit,GABA A Receptor rho Subunit,GABA A Receptors,GABA Benzodiazepine Receptor,GABA Benzodiazepine Receptors,Receptor, Benzodiazepine,Receptor, Benzodiazepine-GABA,Receptor, Diazepam,Receptor, GABA-A,Receptor, GABA-Benzodiazepine,Receptor, Muscimol,Receptors, Benzodiazepine GABA,Receptors, GABA A,Receptors, GABA Benzodiazepine,delta Subunit, GABA A Receptor,epsilon Subunit, GABA A Receptor,gamma Aminobutyric Acid Subtype A Receptors
D002478	Cells, Cultured	Cells propagated in vitro in special media conducive to their growth. Cultured cells are used to study developmental, morphologic, metabolic, physiologic, and genetic processes, among others.	Cultured Cells,Cell, Cultured,Cultured Cell
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
D001534	Bemegride	A CNS stimulant that is used to induce convulsions in experimental animals. It has also been used as a respiratory stimulant and in the treatment of barbiturate overdose.	Ethylmethylglutarimide,Methetharimide,Megimide
D001640	Bicuculline	An isoquinoline alkaloid obtained from Dicentra cucullaria and other plants. It is a competitive antagonist for GABA-A receptors.	6-(5,6,7,8-Tetrahydro-6-methyl-1,3-dioxolo(4,5-g)isoquinolin-5-yl)furo(3,4-e)1,3-benzodioxol-8(6H)one