Biomaterial Database

Species-dependent functional properties of non-NMDA receptors expressed in Xenopus laevis oocytes injected with mammalian and avian brain mRNA. 1994

D Bowie, and T G Smart

Department of Pharmacology, School of Pharmacy, University of London.

1. Species-dependent variation in the functional properties of non-NMDA receptors was investigated by intracellular recording in Xenopus laevis oocytes injected with rat, chick and calf brain mRNA. 2. In all mRNA-injected oocytes, kainic acid (KA), domoic acid (Dom) and 5-bromowillardiine (BrW) evoked large, maintained membrane currents, in contrast to the smaller, desensitizing responses elicited by alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA), quisqualic acid (QA) and L-glutamic acid (L-Glu). Dose-response curves for KA in oocytes injected with calf (EC50 = 96.4 +/- 12.3 microM; mean +/- s.e. mean), chick (87.0 +/- 8.9 microM) or rat (88.7 +/- 4.3 microM) brain mRNA were similar. 3. Current-voltage (I-V) relationships determined with KA inwardly rectified in oocytes injected with calf or chick mRNA; whereas, outward rectification was observed in oocytes injected with rat brain mRNA. 4. In oocytes injected with rat brain mRNA, AMPA antagonized responses evoked by KA in a competitive manner. The absolute amplitudes of KA and AMPA responses in the same oocytes were significantly correlated, which is consistent with both agonists acting on the same receptor-ionophore complex. 5. In contrast, in oocytes injected with calf or chick brain mRNA, AMPA (QA and L-Glu) antagonized the response evoked by KA in a non-competitive manner. The response amplitudes of KA compared to AMPA, QA or L-Glu in the same oocytes were not correlated suggesting discrete receptor-ionophores. 6. This study favours the existence of distinct non-NMDA receptor subtypes that are equi-sensitive to KA. The expressed receptors from different species of mRNA may be distinguished by their voltage sensitivities and the type of antagonism exerted by AMPA on KA-activated responses. Our observations may reflect further heterogeneity of non-NMDA receptors in the central nervous system of different vertebrate species.

UI	MeSH Term	Description	Entries
D007608	Kainic Acid	(2S-(2 alpha,3 beta,4 beta))-2-Carboxy-4-(1-methylethenyl)-3-pyrrolidineacetic acid. Ascaricide obtained from the red alga Digenea simplex. It is a potent excitatory amino acid agonist at some types of excitatory amino acid receptors and has been used to discriminate among receptor types. Like many excitatory amino acid agonists it can cause neurotoxicity and has been used experimentally for that purpose.	Digenic Acid,Kainate,Acid, Digenic,Acid, Kainic
D007700	Kinetics	The rate dynamics in chemical or physical systems.
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
D009865	Oocytes	Female germ cells derived from OOGONIA and termed OOCYTES when they enter MEIOSIS. The primary oocytes begin meiosis but are arrested at the diplotene state until OVULATION at PUBERTY to give rise to haploid secondary oocytes or ova (OVUM).	Ovocytes,Oocyte,Ovocyte
D001923	Brain Chemistry	Changes in the amounts of various chemicals (neurotransmitters, receptors, enzymes, and other metabolites) specific to the area of the central nervous system contained within the head. These are monitored over time, during sensory stimulation, or under different disease states.	Chemistry, Brain,Brain Chemistries,Chemistries, Brain
D002417	Cattle	Domesticated bovine animals of the genus Bos, usually kept on a farm or ranch and used for the production of meat or dairy products or for heavy labor.	Beef Cow,Bos grunniens,Bos indicus,Bos indicus Cattle,Bos taurus,Cow,Cow, Domestic,Dairy Cow,Holstein Cow,Indicine Cattle,Taurine Cattle,Taurus Cattle,Yak,Zebu,Beef Cows,Bos indicus Cattles,Cattle, Bos indicus,Cattle, Indicine,Cattle, Taurine,Cattle, Taurus,Cattles, Bos indicus,Cattles, Indicine,Cattles, Taurine,Cattles, Taurus,Cow, Beef,Cow, Dairy,Cow, Holstein,Cows,Dairy Cows,Domestic Cow,Domestic Cows,Indicine Cattles,Taurine Cattles,Taurus Cattles,Yaks,Zebus
D002645	Chickens	Common name for the species Gallus gallus, the domestic fowl, in the family Phasianidae, order GALLIFORMES. It is descended from the red jungle fowl of SOUTHEAST ASIA.	Gallus gallus,Gallus domesticus,Gallus gallus domesticus,Chicken
D005260	Female		Females
D005971	Glutamates	Derivatives of GLUTAMIC ACID. Included under this heading are a broad variety of acid forms, salts, esters, and amides that contain the 2-aminopentanedioic acid structure.	Glutamic Acid Derivatives,Glutamic Acids,Glutaminic Acids
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