Biomaterial Database

Some effects of d-tubocurarine alone and combined with halothane or isoflurane on neuromuscular transmission. 1995

M D Sokoll, and B J Bhattacharyya, and L R Davies, and D Q Zwagerman

Department of Anesthesia Laboratories, University of Iowa College of Medicine, Iowa City, USA.

The mechanisms contributing to the neuromuscular block produced by nondepolarizing muscle relaxants and inhaled anesthetics include: 1) receptor blockade, 2) open or closed ion channel block, 3) decreased transmitter release, and 4) receptor desensitization. In this study we investigated the contributions of receptor and ion channel block. We used the two microelectrode voltage clamp to evaluate miniature end-plate currents (MEPCs) for amplitude and time constant of decay (tau) before and after the application of 1) d-Tubocurarine (DTC) (10(-7)-10(-6) M) alone, and then 2) the same concentration of DTC plus 0.5% or 1.0% halothane or isoflurane delivered by passing compressed air through a flow and temperature compensated vaporizer. The electrodes were maintained in the same cell for the entire experiment. DTC alone decreased MEPC amplitude to 91.3% +/- 4.5% and 65.1% +/- 5.6% of control at 10(-7) and 10(-6) M, respectively. MEPC amplitude with 10(-6) M DTC decreased further to 52.4% +/- 7.6% and 37.4% +/- 7.0% of control after the addition of 0.5% and 1.0% halothane, respectively. After the application of DTC 10(-7) M tau was 94.7% +/- 3.1% of control and decreased to 73.7% +/- 7.1% of control with 10(-6) M DTC. After the application of DTC 10(-6) M the addition of 0.5% and 1% halothane decreased tau to 52.4% +/- 7.6% and 30.0% +/- 5.9% of control. Isoflurane produced similar changes. This study provides evidence that at least some of the augmentation of nondepolarizing relaxants by inhaled anesthetics can be explained by the additive effect of nondepolarizing muscle relaxants and inhaled anesthetics on MEPC amplitude and tau.

UI	MeSH Term	Description	Entries
D007530	Isoflurane	A stable, non-explosive inhalation anesthetic, relatively free from significant side effects.
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
D009469	Neuromuscular Junction	The synapse between a neuron and a muscle.	Myoneural Junction,Nerve-Muscle Preparation,Junction, Myoneural,Junction, Neuromuscular,Junctions, Myoneural,Junctions, Neuromuscular,Myoneural Junctions,Nerve Muscle Preparation,Nerve-Muscle Preparations,Neuromuscular Junctions,Preparation, Nerve-Muscle,Preparations, Nerve-Muscle
D011898	Ranidae	The family of true frogs of the order Anura. The family occurs worldwide except in Antarctica.	Frogs, True,Rana,Frog, True,True Frog,True Frogs
D003473	Neuromuscular Nondepolarizing Agents	Drugs that interrupt transmission at the skeletal neuromuscular junction without causing depolarization of the motor end plate. They prevent acetylcholine from triggering muscle contraction and are used as muscle relaxants during electroshock treatments, in convulsive states, and as anesthesia adjuvants.	Curare-Like Agents,Curariform Drugs,Muscle Relaxants, Non-Depolarizing,Neuromuscular Blocking Agents, Competitive,Nondepolarizing Blockers,Agents, Curare-Like,Agents, Neuromuscular Nondepolarizing,Blockers, Nondepolarizing,Curare Like Agents,Drugs, Curariform,Muscle Relaxants, Non Depolarizing,Non-Depolarizing Muscle Relaxants,Nondepolarizing Agents, Neuromuscular
D006221	Halothane	A nonflammable, halogenated, hydrocarbon anesthetic that provides relatively rapid induction with little or no excitement. Analgesia may not be adequate. NITROUS OXIDE is often given concomitantly. Because halothane may not produce sufficient muscle relaxation, supplemental neuromuscular blocking agents may be required. (From AMA Drug Evaluations Annual, 1994, p178)	1,1,1-Trifluoro-2-Chloro-2-Bromoethane,Fluothane,Ftorotan,Narcotan
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
D014403	Tubocurarine	A neuromuscular blocker and active ingredient in CURARE; plant based alkaloid of Menispermaceae.	Tubocurare,Tubocurarine Chloride,d-Tubocurare,d-Tubocurarine
D018408	Patch-Clamp Techniques	An electrophysiologic technique for studying cells, cell membranes, and occasionally isolated organelles. All patch-clamp methods rely on a very high-resistance seal between a micropipette and a membrane; the seal is usually attained by gentle suction. The four most common variants include on-cell patch, inside-out patch, outside-out patch, and whole-cell clamp. Patch-clamp methods are commonly used to voltage clamp, that is control the voltage across the membrane and measure current flow, but current-clamp methods, in which the current is controlled and the voltage is measured, are also used.	Patch Clamp Technique,Patch-Clamp Technic,Patch-Clamp Technique,Voltage-Clamp Technic,Voltage-Clamp Technique,Voltage-Clamp Techniques,Whole-Cell Recording,Patch-Clamp Technics,Voltage-Clamp Technics,Clamp Technique, Patch,Clamp Techniques, Patch,Patch Clamp Technic,Patch Clamp Technics,Patch Clamp Techniques,Recording, Whole-Cell,Recordings, Whole-Cell,Technic, Patch-Clamp,Technic, Voltage-Clamp,Technics, Patch-Clamp,Technics, Voltage-Clamp,Technique, Patch Clamp,Technique, Patch-Clamp,Technique, Voltage-Clamp,Techniques, Patch Clamp,Techniques, Patch-Clamp,Techniques, Voltage-Clamp,Voltage Clamp Technic,Voltage Clamp Technics,Voltage Clamp Technique,Voltage Clamp Techniques,Whole Cell Recording,Whole-Cell Recordings
D018680	Cholinergic Antagonists	Drugs that bind to but do not activate CHOLINERGIC RECEPTORS, thereby blocking the actions of ACETYLCHOLINE or cholinergic agonists.	Acetylcholine Antagonist,Acetylcholine Antagonists,Anti-Cholinergic,Anticholinergic,Anticholinergic Agent,Anticholinergic Agents,Cholinergic Receptor Antagonist,Cholinergic-Blocking Agent,Cholinergic-Blocking Agents,Cholinolytic,Cholinolytics,Anti-Cholinergics,Anticholinergics,Cholinergic Antagonist,Cholinergic Receptor Antagonists,Agent, Anticholinergic,Agent, Cholinergic-Blocking,Agents, Anticholinergic,Agents, Cholinergic-Blocking,Antagonist, Acetylcholine,Antagonist, Cholinergic,Antagonist, Cholinergic Receptor,Antagonists, Acetylcholine,Antagonists, Cholinergic,Antagonists, Cholinergic Receptor,Anti Cholinergic,Anti Cholinergics,Cholinergic Blocking Agent,Cholinergic Blocking Agents,Receptor Antagonist, Cholinergic,Receptor Antagonists, Cholinergic