Biomaterial Database

Membrane properties of dissociated trigeminal mesencephalic neurons of the adult rat. 1998

S Yoshida, and H Oka

Department of Physiology, Fukui Medical School, Japan. shig@fmsrsa.fukui-med.ac.jp

Electrophysiological properties of pseudounipolar trigeminal mesencephalic (Me5) neurons, dissociated from the rat brain, were studied under current-clamp conditions using the whole-cell configuration. Almost all Me5 neurons (37/38, 97%) exhibited a rapid adaptation in response to long depolarizing current pulses. Another firing type, slowly-adapting, was observed in only 3% of neurons (1/38). Most Me5 neurons (42/43) generated an overshooting action potential without a hump on the falling phase, and the remaining neuron (1/43) showed an action potential with a small hump. The action potential of Me5 neurons was reversibly blocked by 1 microM tetrodotoxin (TTX) or by removing Na+ from the bathing medium. When the outward K+ current was suppressed, two types of Ca2+ spikes were revealed. According to characteristic thresholds and sensitivity to inorganic (Ni2+, Cd2+) and organic (nifedipine, omega-conotoxin GVIA) Ca2+ channel blockers, these Ca2+ spikes were identified as T-type LTS (low-threshold spike) and L-type HTS (high-threshold spike). Also, a time-dependent inward rectification was observed in all Me5 neurons. It is concluded that the majority of Me5 neurons are of the rapidly-adapting type and generate a TTX-sensitive Na+ spike with negligible contribution of Ca2+, showing that the electrophysiological properties of Me5 neurons are more similar to those of CNS neurons than to those of PNS ganglion cells which have similar morphological features to Me5 neurons.

UI	MeSH Term	Description	Entries
D008636	Mesencephalon	The middle of the three primitive cerebral vesicles of the embryonic brain. Without further subdivision, midbrain develops into a short, constricted portion connecting the PONS and the DIENCEPHALON. Midbrain contains two major parts, the dorsal TECTUM MESENCEPHALI and the ventral TEGMENTUM MESENCEPHALI, housing components of auditory, visual, and other sensorimoter systems.	Midbrain,Mesencephalons,Midbrains
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
D009475	Neurons, Afferent	Neurons which conduct NERVE IMPULSES to the CENTRAL NERVOUS SYSTEM.	Afferent Neurons,Afferent Neuron,Neuron, Afferent
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
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
D002490	Central Nervous System	The main information-processing organs of the nervous system, consisting of the brain, spinal cord, and meninges.	Cerebrospinal Axis,Axi, Cerebrospinal,Axis, Cerebrospinal,Central Nervous Systems,Cerebrospinal Axi,Nervous System, Central,Nervous Systems, Central,Systems, Central Nervous
D002531	Cerebellum	The part of brain that lies behind the BRAIN STEM in the posterior base of skull (CRANIAL FOSSA, POSTERIOR). It is also known as the "little brain" with convolutions similar to those of CEREBRAL CORTEX, inner white matter, and deep cerebellar nuclei. Its function is to coordinate voluntary movements, maintain balance, and learn motor skills.	Cerebella,Corpus Cerebelli,Parencephalon,Cerebellums,Parencephalons
D004594	Electrophysiology	The study of the generation and behavior of electrical charges in living organisms particularly the nervous system and the effects of electricity on living organisms.
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
D000222	Adaptation, Physiological	The non-genetic biological changes of an organism in response to challenges in its ENVIRONMENT.	Adaptation, Physiologic,Adaptations, Physiologic,Adaptations, Physiological,Adaptive Plasticity,Phenotypic Plasticity,Physiological Adaptation,Physiologic Adaptation,Physiologic Adaptations,Physiological Adaptations,Plasticity, Adaptive,Plasticity, Phenotypic