Biomaterial Database

Electrical properties of facial motoneurons in brainstem slices from guinea pig. 1989

Y Nishimura, and P C Schwindt, and W E Crill

Department of Physiology and Biophysics, University of Washington School of Medicine, Seattle 98195.

Electrical properties of guinea pig facial motoneurons (FMNs) were studied in a brainstem slice preparation. FMNs were identified histologically and by antidromic activation. They displayed time-varying responses and inward rectification during both subthreshold depolarization and hyperpolarization. The depolarizing rectification was caused by a persistent Na+ current (INaP); the Cs+-sensitive hyperpolarizing response had a different mechanism. Hyperpolarizing prepulses caused a 4-aminopyridine-sensitive delay of spike initiation. An evoked spike was followed by a fast- and a medium-duration hyperpolarization (the fAHP and mAHP, respectively). Blockade of Ca2+ influx abolished the mAHP without affecting spike duration, whereas spikes were prolonged and the fAHP was abolished by TEA or 4-AP. Adequate depolarization evoked tonic repetitive firing characterized by a steep F-I slope and fast adaptation. Abolition of the mAHP was associated with reduced fast adaptation and increased F-I slope, whereas the mAHP was enhanced and firing rate was slowed after TEA application. Three outward ionic currents were identified during voltage clamp: a rapidly inactivating current, a slowly inactivating current and a slow persistent Ca2+-mediated current (IK(Ca]. We conclude that spike repolarization and the fAHP are governed mainly by fast voltage-dependent currents, whereas progressive activation of IK(Ca) causes fast adaptation and, together with INaP, regulates firing rate.

UI	MeSH Term	Description	Entries
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
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
D002118	Calcium	A basic element found in nearly all tissues. It is a member of the alkaline earth family of metals with the atomic symbol Ca, atomic number 20, and atomic weight 40. Calcium is the most abundant mineral in the body and combines with phosphorus to form calcium phosphate in the bones and teeth. It is essential for the normal functioning of nerves and muscles and plays a role in blood coagulation (as factor IV) and in many enzymatic processes.	Coagulation Factor IV,Factor IV,Blood Coagulation Factor IV,Calcium-40,Calcium 40,Factor IV, Coagulation
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
D005154	Facial Nerve	The 7th cranial nerve. The facial nerve has two parts, the larger motor root which may be called the facial nerve proper, and the smaller intermediate or sensory root. Together they provide efferent innervation to the muscles of facial expression and to the lacrimal and SALIVARY GLANDS, and convey afferent information for TASTE from the anterior two-thirds of the TONGUE and for TOUCH from the EXTERNAL EAR.	Cranial Nerve VII,Marginal Mandibular Branch,Marginal Mandibular Nerve,Seventh Cranial Nerve,Nerve VII,Nerve of Wrisberg,Nervus Facialis,Nervus Intermedius,Nervus Intermedius of Wrisberg,Cranial Nerve VIIs,Cranial Nerve, Seventh,Facial Nerves,Mandibular Nerve, Marginal,Mandibular Nerves, Marginal,Marginal Mandibular Nerves,Nerve VIIs,Nerve, Facial,Nerve, Marginal Mandibular,Nerve, Seventh Cranial,Nerves, Marginal Mandibular,Nervus Faciali,Seventh Cranial Nerves,Wrisberg Nerve,Wrisberg Nervus Intermedius
D005260	Female		Females
D006168	Guinea Pigs	A common name used for the genus Cavia. The most common species is Cavia porcellus which is the domesticated guinea pig used for pets and biomedical research.	Cavia,Cavia porcellus,Guinea Pig,Pig, Guinea,Pigs, Guinea
D000200	Action Potentials	Abrupt changes in the membrane potential that sweep along the CELL MEMBRANE of excitable cells in response to excitation stimuli.	Spike Potentials,Nerve Impulses,Action Potential,Impulse, Nerve,Impulses, Nerve,Nerve Impulse,Potential, Action,Potential, Spike,Potentials, Action,Potentials, Spike,Spike Potential
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