Biomaterial Database

Glutamate metabotropic receptor inhibition of voltage-gated calcium currents in visceral sensory neurons. 1994

M Hay, and D L Kunze

Department of Molecular Physiology and Biophysics, Baylor College of Medicine, Houston, Texas 77030.

1. Metabotropic glutamate receptors (mGluRs) have been suggested to modulate neurotransmission of glutamatergic pathways via autoreceptive action. Visceral sensory afferents and baroreceptor afferents in particular are thought to utilize L-glutamate (L-glu) as a primary neurotransmitter. The purpose of this study was to investigate whether visceral sensory afferents possess a mGluR and determine the effect of mGluR activation on voltage-gated calcium currents in these neurons. 2. Activation of mGluRs by the selective agonist trans-(+/-)-1-amino-1,3-cyclopentanedicarboxylic acid (t-ACPD) reversibly suppressed the voltage-gated calcium currents in visceral sensory afferents of the nodose ganglion. Concentrations of t-ACPD ranging from 50 to 1,000 microM consistently decreased the evoked calcium current with a maximum suppression of the peak current of 25-30%. This response was repeatable and reversible within a given cell. 3. Metabotropic GluR activation selectively decreased the high-threshold calcium current evoked from step potentials greater than -30 mV and had no effect on the low-threshold calcium current. The inhibitory effects of t-ACPD on the high-threshold channel was partially blocked by omega-conotoxin (omega-CTx-GVIA) suggesting that at least part of the effects of mGluR inhibition of the voltage-gated calcium current is because of a modulation of the omega-CTx-GVIA sensitive high-threshold current. 4. Finally, the inhibitory effects of quisqualate (quis) on the high-threshold calcium current were blocked by pretreatment of the neurons with pertussis toxin (PTX). These results suggest that visceral sensory afferents do possess a PTX-sensitive mGluR and activation of this receptor results in the inhibition of a omega-CTx-GVIA sensitive high-threshold calcium channel.

UI	MeSH Term	Description	Entries
D009433	Neural Inhibition	The function of opposing or restraining the excitation of neurons or their target excitable cells.	Inhibition, Neural
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
D009620	Nodose Ganglion	The inferior (caudal) ganglion of the vagus (10th cranial) nerve. The unipolar nodose ganglion cells are sensory cells with central projections to the medulla and peripheral processes traveling in various branches of the vagus nerve.	Nodose Ganglia,Ganglia, Nodose,Ganglion, Nodose
D011984	Sensory Receptor Cells	Specialized afferent neurons capable of transducing sensory stimuli into NERVE IMPULSES to be transmitted to the CENTRAL NERVOUS SYSTEM. Sometimes sensory receptors for external stimuli are called exteroceptors; for internal stimuli are called interoceptors and proprioceptors.	Nerve Endings, Sensory,Neurons, Sensory,Neuroreceptors,Receptors, Neural,Neural Receptors,Receptors, Sensory,Sensory Neurons,Sensory Receptors,Nerve Ending, Sensory,Neural Receptor,Neuron, Sensory,Neuroreceptor,Receptor Cell, Sensory,Receptor Cells, Sensory,Receptor, Neural,Receptor, Sensory,Sensory Nerve Ending,Sensory Nerve Endings,Sensory Neuron,Sensory Receptor,Sensory Receptor Cell
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
D005071	Evoked Potentials	Electrical responses recorded from nerve, muscle, SENSORY RECEPTOR, or area of the CENTRAL NERVOUS SYSTEM following stimulation. They range from less than a microvolt to several microvolts. The evoked potential can be auditory (EVOKED POTENTIALS, AUDITORY), somatosensory (EVOKED POTENTIALS, SOMATOSENSORY), visual (EVOKED POTENTIALS, VISUAL), or motor (EVOKED POTENTIALS, MOTOR), or other modalities that have been reported.	Event Related Potential,Event-Related Potentials,Evoked Potential,N100 Evoked Potential,P50 Evoked Potential,N1 Wave,N100 Evoked Potentials,N2 Wave,N200 Evoked Potentials,N3 Wave,N300 Evoked Potentials,N4 Wave,N400 Evoked Potentials,P2 Wave,P200 Evoked Potentials,P50 Evoked Potentials,P50 Wave,P600 Evoked Potentials,Potentials, Event-Related,Event Related Potentials,Event-Related Potential,Evoked Potential, N100,Evoked Potential, N200,Evoked Potential, N300,Evoked Potential, N400,Evoked Potential, P200,Evoked Potential, P50,Evoked Potential, P600,Evoked Potentials, N100,Evoked Potentials, N200,Evoked Potentials, N300,Evoked Potentials, N400,Evoked Potentials, P200,Evoked Potentials, P50,Evoked Potentials, P600,N1 Waves,N2 Waves,N200 Evoked Potential,N3 Waves,N300 Evoked Potential,N4 Waves,N400 Evoked Potential,P2 Waves,P200 Evoked Potential,P50 Waves,P600 Evoked Potential,Potential, Event Related,Potential, Event-Related,Potential, Evoked,Potentials, Event Related,Potentials, Evoked,Potentials, N400 Evoked,Related Potential, Event,Related Potentials, Event,Wave, N1,Wave, N2,Wave, N3,Wave, N4,Wave, P2,Wave, P50,Waves, N1,Waves, N2,Waves, N3,Waves, N4,Waves, P2,Waves, P50
D000344	Afferent Pathways	Nerve structures through which impulses are conducted from a peripheral part toward a nerve center.	Afferent Pathway,Pathway, Afferent,Pathways, Afferent
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
D000831	Animals, Newborn	Refers to animals in the period of time just after birth.	Animals, Neonatal,Animal, Neonatal,Animal, Newborn,Neonatal Animal,Neonatal Animals,Newborn Animal,Newborn Animals
D012684	Sensory Thresholds	The minimum amount of stimulus energy necessary to elicit a sensory response.	Sensory Threshold,Threshold, Sensory,Thresholds, Sensory