Biomaterial Database

Thyrotropin-releasing hormone causes excitation of rat hypoglossal motoneurons in vitro. 1993

D A Bayliss, and F Viana, and A J Berger

Department of Physiology and Biophysics, University of Washington School of Medicine, Seattle.

A brainstem slice preparation and conventional intracellular recording techniques were used to study the effects of the neuropeptide thyrotropin-releasing hormone (TRH) on adult rat hypoglossal motoneurons (HMs) in vitro. We found that TRH (0.1-10 microM) had two effects: 1) it caused depolarization of HMs and 2) decreased their input conductance. We tested the effects of TRH on HMs using a sinusoidal current injection paradigm to approximate the rhythmic activity of HMs in vivo. Waves of injected current that elicited only subthreshold behavior in control conditions caused repetitive firing in the presence of TRH. Compensating for the TRH-induced depolarization by hyperpolarizing direct current injection revealed the consequences of decreased input conductance in isolation. Under these conditions, the spike-firing of HMs at the peak of the sinusoid was still enhanced. In addition, the maximal hyperpolarization at the nadir of the current wave was also increased. This suggests that in the presence of TRH, the effects of both excitatory and inhibitory synaptic inputs on HMs are enhanced and the contrast between excitation and inhibition is sharpened.

UI	MeSH Term	Description	Entries
D007002	Hypoglossal Nerve	The 12th cranial nerve. The hypoglossal nerve originates in the hypoglossal nucleus of the medulla and supplies motor innervation to all of the muscles of the tongue except the palatoglossus (which is supplied by the vagus). This nerve also contains proprioceptive afferents from the tongue muscles.	Cranial Nerve XII,Twelfth Cranial Nerve,Nerve XII,Nervus Hypoglossus,Cranial Nerve XIIs,Cranial Nerve, Twelfth,Cranial Nerves, Twelfth,Hypoglossal Nerves,Hypoglossus, Nervus,Nerve XII, Cranial,Nerve XIIs,Nerve XIIs, Cranial,Nerve, Hypoglossal,Nerve, Twelfth Cranial,Nerves, Hypoglossal,Nerves, Twelfth Cranial,Twelfth Cranial Nerves,XII, Nerve,XIIs, Nerve
D008297	Male		Males
D009046	Motor Neurons	Neurons which activate MUSCLE CELLS.	Neurons, Motor,Alpha Motorneurons,Motoneurons,Motor Neurons, Alpha,Neurons, Alpha Motor,Alpha Motor Neuron,Alpha Motor Neurons,Alpha Motorneuron,Motoneuron,Motor Neuron,Motor Neuron, Alpha,Motorneuron, Alpha,Motorneurons, Alpha,Neuron, Alpha Motor,Neuron, Motor
D009431	Neural Conduction	The propagation of the NERVE IMPULSE along the nerve away from the site of an excitation stimulus.	Nerve Conduction,Conduction, Nerve,Conduction, Neural,Conductions, Nerve,Conductions, Neural,Nerve Conductions,Neural Conductions
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
D011903	Raphe Nuclei	Collections of small neurons centrally scattered among many fibers from the level of the TROCHLEAR NUCLEUS in the midbrain to the hypoglossal area in the MEDULLA OBLONGATA.	Caudal Linear Nucleus of the Raphe,Interfascicular Nucleus,Nucleus Incertus,Rostral Linear Nucleus of Raphe,Rostral Linear Nucleus of the Raphe,Superior Central Nucleus,Central Nucleus, Superior,Incertus, Nucleus,Nuclei, Raphe,Nucleus, Interfascicular,Nucleus, Raphe,Nucleus, Superior Central,Raphe Nucleus
D012123	Pulmonary Ventilation	The total volume of gas inspired or expired per unit of time, usually measured in liters per minute.	Respiratory Airflow,Ventilation Tests,Ventilation, Pulmonary,Expiratory Airflow,Airflow, Expiratory,Airflow, Respiratory,Test, Ventilation,Tests, Ventilation,Ventilation Test
D001933	Brain Stem	The part of the brain that connects the CEREBRAL HEMISPHERES with the SPINAL CORD. It consists of the MESENCEPHALON; PONS; and MEDULLA OBLONGATA.	Brainstem,Truncus Cerebri,Brain Stems,Brainstems,Cerebri, Truncus,Cerebrus, Truncus,Truncus Cerebrus
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
D005260	Female		Females