16 research outputs found
Lack of Evidence of an Interaction between Leu-Enkephalin and Muscarinic-Like Responses in the Frog Semicircular Canal
Dopaminergic Modulation of Afferent Synaptic Transmission in the Semicircular Canals of Frogs
Effects of acetylcholine and cholinolytics on the synaptic transmission in the ampullae of Lorenzini of the skate
Comparative analysis of the effect of endogenous antibiotic defensin NP-1 and aminoglycoside antibiotic gentamicin on synaptic transmission in receptors of the frog vestibular apparatus
Immunocytochemical and pharmacological characterization of metabotropic glutamate receptors of the vestibular end organs in the frog.
Using immunocytochemistry and multiunit recording of afferent activity of the whole vestibular nerve, we investigated the role of metabotropic glutamate receptors (mGluR) in the afferent neurotransmission in the frog semicircular canals (SCC). Group I (mGluR1alpha) and group II (mGluR2/3) mGluR immunoreactivities were distributed to the vestibular ganglion neurons, and this can be attributed to a postsynaptic locus of metabotropic regulation of rapid excitatory transmission. The effects of group I/II mGluR agonist (1S,3R)-1-aminocyclopentane-trans-1,3-dicarboxylic acid (ACPD) and antagonist (R,S)-alpha-methyl-4-carboxyphenylglycine (MCPG) on resting and chemically induced afferent activity were studied. ACPD (10-100 microM) enhanced the resting discharge frequency. MCPG (5-100 microM) led to a concentration-dependent decrease of both resting activity and ACPD-induced responses. If the discharge frequency had previously been restored by L-glutamate (L-Glu) in high-Mg2+ solution, ACPD elicited a transient increase in the firing rate in the afferent nerve suggesting that ACPD acts on postsynaptic receptors. The L-Glu agonists, alpha-amino-3-hydroxy-5-methylisoxazole-4-propionate (AMPA) and N-methyl-D-aspartate (NMDA), were tested during application of ACPD. AMPA- and NMDA-induced responses were higher in the presence than absence of ACPD, implicating mGluR in the modulation of ionotropic glutamate receptors. These results indicate that activation of mGluR potentiates AMPA and NMDA responses through a postsynaptic interaction. We conclude that ACPD may exert modulating postsynaptic effects on vestibular afferents and that this process is activity-dependent
Antagonists D1 and D2 of Dopamine Receptors Determine Different Mechanisms of Neuroprotective Action in the Frog Vestibular
Responses of electroreceptors (ampullae of lorenzini) of Skates to electric and magnetic fields
Synthesis of Stable Bismuth Silicate with Sillenite Structure in the Na2O–Bi2O3–SiO2 System
Composition, density and structure dependent neutron yields from deuterated targets in high-intensity laser shot
Experimental studies are presented on composition, density and
structure influence onto the neutron yield resulting from
deuterium-containing target interaction with laser light of
10 W/cm. Experimental data are compared with
theoretical and simulation results