Biomaterial Database

Differential effects of (D)- and (L)-homocysteic acid on the membrane potential of cat caudate neurons in situ. 1989

P L Herrling, and J Maeder, and C L Meier, and K Q Do

Sandoz Research Institute, Berne, Switzerland.

The enantiomers of homocysteic acid have been applied by microiontophoresis to neurons of the cat caudate nucleus in situ. The (L)-enantiomer elicited a bursty firing pattern similar to the one caused by N-methyl-D-aspartate, but differing from the N-methyl-D-aspartate pattern inasmuch as (L)-homocysteate induced depolarization shifts were shorter and had a smaller amplitude. (L)-Homocysteate induced excitations could be strongly inhibited by the selective N-methyl-D-aspartate antagonist 2-amino-7-phosphonoheptanoic acid but they were less sensitive to this antagonist than N-methyl-D-aspartate itself. (D)-Homocysteate elicited a more regular firing pattern similar to the one caused by non-N-methyl-D-aspartate excitatory amino acids such as quisqualate. These excitations were only rarely inhibited by 2-amino-7-phosphonoheptanoic acid. Our results suggest that (L)-homocysteate, a transmitter candidate at central mammalian synapses, is a mixed excitatory amino acid agonist with a strong preference for N-methyl-D-aspartate receptors in the cat caudate nucleus, while (D)-homocysteate has a predominant action at non-N-methyl-D-aspartate excitatory amino acid receptors.

UI	MeSH Term	Description	Entries
D008297	Male		Males
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
D002415	Cats	The domestic cat, Felis catus, of the carnivore family FELIDAE, comprising over 30 different breeds. The domestic cat is descended primarily from the wild cat of Africa and extreme southwestern Asia. Though probably present in towns in Palestine as long ago as 7000 years, actual domestication occurred in Egypt about 4000 years ago. (From Walker's Mammals of the World, 6th ed, p801)	Felis catus,Felis domesticus,Domestic Cats,Felis domestica,Felis sylvestris catus,Cat,Cat, Domestic,Cats, Domestic,Domestic Cat
D002421	Caudate Nucleus	Elongated gray mass of the neostriatum located adjacent to the lateral ventricle of the brain.	Caudatus,Nucleus Caudatus,Caudatus, Nucleus,Nucleus, Caudate
D005260	Female		Females
D006710	Homocysteine	A thiol-containing amino acid formed by a demethylation of METHIONINE.	2-amino-4-mercaptobutyric acid,Homocysteine, L-Isomer,2 amino 4 mercaptobutyric acid,Homocysteine, L Isomer,L-Isomer Homocysteine
D000200	Action Potentials	Abrupt changes in the membrane potential that sweep along the CELL MEMBRANE of excitable cells in response to excitation stimuli.	Spike Potentials,Nerve Impulses,Action Potential,Impulse, Nerve,Impulses, Nerve,Nerve Impulse,Potential, Action,Potential, Spike,Potentials, Action,Potentials, Spike,Spike Potential
D000596	Amino Acids	Organic compounds that generally contain an amino (-NH2) and a carboxyl (-COOH) group. Twenty alpha-amino acids are the subunits which are polymerized to form proteins.	Amino Acid,Acid, Amino,Acids, Amino
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
D013237	Stereoisomerism	The phenomenon whereby compounds whose molecules have the same number and kind of atoms and the same atomic arrangement, but differ in their spatial relationships. (From McGraw-Hill Dictionary of Scientific and Technical Terms, 5th ed)	Molecular Stereochemistry,Stereoisomers,Stereochemistry, Molecular,Stereoisomer