Effect of delta 9-tetrahydrocannabinol on synaptic transmission in the electric eel electroplaque. 1979

W D Niemi

When the innervated membrane of the electric eel electroplaque is exposed to concentrations of delta 9-tetracannabinol of 50 to 100 microM synaptic transmission is blocked in approximately 30 minutes. During the block, the chemosensitivity of the innervated membrane to cholinergic agonists remains unaltered. Direct stimulation of the innervated membrane after synaptic transmission had failed did not elicit any postsynaptic membrane action potentials. The passing of hyperpolarizing currents across the electroplaque caused the nerve terminals which innervate the electroplaque to produce subthreshold potentials which resemble endplate potentials with a prolonged falling phase. With further incubation in the tetrahydrocannabinol solution the subthreshold potentials decreased in size and eventually disappeared. These results indicate that delta 9-tetrahydrocannabinol does not affect the acetylcholine-mediated membrane permeability changes, but instead, reduces the excitability of nonsynaptic membrane of both the pre- and postsynaptic elements.

UI MeSH Term Description Entries
D009045 Motor Endplate The specialized postsynaptic region of a muscle cell. The motor endplate is immediately across the synaptic cleft from the presynaptic axon terminal. Among its anatomical specializations are junctional folds which harbor a high density of cholinergic receptors. Motor End-Plate,End-Plate, Motor,End-Plates, Motor,Endplate, Motor,Endplates, Motor,Motor End Plate,Motor End-Plates,Motor Endplates
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
D002217 Carbachol A slowly hydrolyzed CHOLINERGIC AGONIST that acts at both MUSCARINIC RECEPTORS and NICOTINIC RECEPTORS. Carbamylcholine,Carbacholine,Carbamann,Carbamoylcholine,Carbastat,Carbocholine,Carboptic,Doryl,Isopto Carbachol,Jestryl,Miostat,Carbachol, Isopto
D004557 Electric Organ In about 250 species of electric fishes, modified muscle fibers forming disklike multinucleate plates arranged in stacks like batteries in series and embedded in a gelatinous matrix. A large torpedo ray may have half a million plates. Muscles in different parts of the body may be modified, i.e., the trunk and tail in the electric eel, the hyobranchial apparatus in the electric ray, and extrinsic eye muscles in the stargazers. Powerful electric organs emit pulses in brief bursts several times a second. They serve to stun prey and ward off predators. A large torpedo ray can produce of shock of more than 200 volts, capable of stunning a human. (Storer et al., General Zoology, 6th ed, p672) Electric Organs,Organ, Electric,Organs, Electric
D004593 Electrophorus A genus of fish, in the family GYMNOTIFORMES, capable of producing an electric shock that immobilizes fish and other prey. The species Electrophorus electricus is also known as the electric eel, though it is not a true eel. Eel, Electric,Electric Eel,Electrophorus electricus
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
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
D013759 Dronabinol A psychoactive compound extracted from the resin of Cannabis sativa (marihuana, hashish). The isomer delta-9-tetrahydrocannabinol (THC) is considered the most active form, producing characteristic mood and perceptual changes associated with this compound. THC,Tetrahydrocannabinol,delta(9)-THC,9-ene-Tetrahydrocannabinol,Marinol,Tetrahydrocannabinol, (6a-trans)-Isomer,Tetrahydrocannabinol, (6aR-cis)-Isomer,Tetrahydrocannabinol, (6aS-cis)-Isomer,Tetrahydrocannabinol, Trans-(+-)-Isomer,Tetrahydrocannabinol, Trans-Isomer,delta(1)-THC,delta(1)-Tetrahydrocannabinol,delta(9)-Tetrahydrocannabinol,9 ene Tetrahydrocannabinol,Tetrahydrocannabinol, Trans Isomer
D066298 In Vitro Techniques Methods to study reactions or processes taking place in an artificial environment outside the living organism. In Vitro Test,In Vitro Testing,In Vitro Tests,In Vitro as Topic,In Vitro,In Vitro Technique,In Vitro Testings,Technique, In Vitro,Techniques, In Vitro,Test, In Vitro,Testing, In Vitro,Testings, In Vitro,Tests, In Vitro,Vitro Testing, In
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