Biomaterial Database

Thyrotropin-releasing hormone enhances excitatory postsynaptic potentials in neocortical neurons of the rat in vitro. 1994

S Kasparov, and H Pawelzik, and W Zieglgänsberger

Moscow Sechenov Medical Academy, Dept. of Pharmacology, Russia.

Several lines of evidence suggest a modulatory effect of thyrotropin-releasing hormone (TRH) on synaptic transmission in the mammalian neocortex. In the present study, the effects of this tripeptide on intracellularly recorded neocortical pyramidal neurons were investigated using rat in vitro brain slice preparations. TRH (5 microM and 50 microM) added to the perfusion medium concentration-dependently increased the excitability of pyramidal neurons, reflected by the number of spikes evoked by a depolarizing current pulse and by the augmentation of the time integral of glutamatergic excitatory postsynaptic potentials (EPSPs). TRH increased preferentially the time integrals of the late components of EPSPs (1-EPSPs) and increased their voltage-dependence. The early components of the EPSPs (e-EPSPs) were changed to much lesser extent. Iontophoretically applied D-2-amino-5-phosphonovalerate (D-APV) antagonized the TRH-induced increase of the 1-EPSPs. TRH also markedly enhanced the depolarizing responses evoked by iontophoretically applied N-methyl-D-aspartate (NMDA), while the depolarizing responses evoked by (R,S)-alpha-amino-3-hydroxy-5-methyl-4-isoxazole-propionic acid (AMPA) and L-glutamate were not significantly affected. The depolarizing inward rectification present in all neurons studied was augmented by the higher concentration of TRH. The effects of TRH were incited after about 5 min and were long-lasting. In most neurons the effects of TRH on neuronal excitability did not completely recover during the 45 min washout period. The present data suggest that some of the non-hormonal actions of TRH in the neocortex may be due to an enhancement of glutamatergic synaptic transmission.(ABSTRACT TRUNCATED AT 250 WORDS)

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
D009435	Synaptic Transmission	The communication from a NEURON to a target (neuron, muscle, or secretory cell) across a SYNAPSE. In chemical synaptic transmission, the presynaptic neuron releases a NEUROTRANSMITTER that diffuses across the synaptic cleft and binds to specific synaptic receptors, activating them. The activated receptors modulate specific ion channels and/or second-messenger systems in the postsynaptic cell. In electrical synaptic transmission, electrical signals are communicated as an ionic current flow across ELECTRICAL SYNAPSES.	Neural Transmission,Neurotransmission,Transmission, Neural,Transmission, Synaptic
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
D002540	Cerebral Cortex	The thin layer of GRAY MATTER on the surface of the CEREBRAL HEMISPHERES that develops from the TELENCEPHALON and folds into gyri and sulci. It reaches its highest development in humans and is responsible for intellectual faculties and higher mental functions.	Allocortex,Archipallium,Cortex Cerebri,Cortical Plate,Paleocortex,Periallocortex,Allocortices,Archipalliums,Cerebral Cortices,Cortex Cerebrus,Cortex, Cerebral,Cortical Plates,Paleocortices,Periallocortices,Plate, Cortical
D004558	Electric Stimulation	Use of electric potential or currents to elicit biological responses.	Stimulation, Electric,Electrical Stimulation,Electric Stimulations,Electrical Stimulations,Stimulation, Electrical,Stimulations, Electric,Stimulations, Electrical
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
D013569	Synapses	Specialized junctions at which a neuron communicates with a target cell. At classical synapses, a neuron's presynaptic terminal releases a chemical transmitter stored in synaptic vesicles which diffuses across a narrow synaptic cleft and activates receptors on the postsynaptic membrane of the target cell. The target may be a dendrite, cell body, or axon of another neuron, or a specialized region of a muscle or secretory cell. Neurons may also communicate via direct electrical coupling with ELECTRICAL SYNAPSES. Several other non-synaptic chemical or electric signal transmitting processes occur via extracellular mediated interactions.	Synapse
D013973	Thyrotropin-Releasing Hormone	A tripeptide that stimulates the release of THYROTROPIN and PROLACTIN. It is synthesized by the neurons in the PARAVENTRICULAR NUCLEUS of the HYPOTHALAMUS. After being released into the pituitary portal circulation, TRH (was called TRF) stimulates the release of TSH and PRL from the ANTERIOR PITUITARY GLAND.	Protirelin,Thyroliberin,Abbott-38579,Antepan,Proterelin Tartrate,Proterelin Tartrate Hydrate,Protirelin Tartrate (1:1),Relefact TRH,Stimu-TSH,TRH Ferring,TRH Prem,Thypinone,Thyroliberin TRH Merck,Thyrotropin-Releasing Factor,Thyrotropin-Releasing Hormone Tartrate,Abbott 38579,Abbott38579,Hydrate, Proterelin Tartrate,Prem, TRH,Stimu TSH,StimuTSH,TRH, Relefact,Tartrate Hydrate, Proterelin,Thyrotropin Releasing Factor,Thyrotropin Releasing Hormone,Thyrotropin Releasing Hormone Tartrate
D015763	2-Amino-5-phosphonovalerate	The D-enantiomer is a potent and specific antagonist of NMDA glutamate receptors (RECEPTORS, N-METHYL-D-ASPARTATE). The L form is inactive at NMDA receptors but may affect the AP4 (2-amino-4-phosphonobutyrate; APB) excitatory amino acid receptors.	2-Amino-5-phosphonopentanoic Acid,2-Amino-5-phosphonovaleric Acid,2-APV,2-Amino-5-phosphonopentanoate,5-Phosphononorvaline,d-APV,dl-APV,2 Amino 5 phosphonopentanoate,2 Amino 5 phosphonopentanoic Acid,2 Amino 5 phosphonovalerate,2 Amino 5 phosphonovaleric Acid,5 Phosphononorvaline