Related Experiment Video
Updated: Aug 17, 2026

Measuring Spinal Presynaptic Inhibition in Mice By Dorsal Root Potential Recording In Vivo
Published on: March 29, 2014
Ketamine acts as a non-competitive N-methyl-D-aspartate antagonist on frog spinal cord in vitro
Abstract:
The effects of the dissociative anaesthetic, ketamine, the divalent cation, magnesium and the organic antagonist, 2-amino-5-phosphonovalerate (APV), were examined on responses of motoneurones to excitatory amino acids in the hemisected spinal cord of the frog in vitro. The amino acids, N-methyl-D-aspartate (NMDA), kainate and quisqualate, produced dose-dependent depolarizations. Ketamine, magnesium and APV depressed responses to NMDA but had no effect on those to quisqualate and kainate. Magnesium and APV produced Schild plot slopes that were not different from unity, whereas ketamine had a slope significantly less than unity, indicative of a non-competitive action. Experiments in which combinations of drugs were tested indicated that these substances act by three distinct mechanisms to cause antagonism of the actions of NMDA.
More Related Videos
17:05Loading a Calcium Dye into Frog Nerve Endings Through the Nerve Stump: Calcium Transient Registration in the Frog Neuromuscular Junction
Published on: July 8, 2017
08:24Zebrafish In Situ Spinal Cord Preparation for Electrophysiological Recordings from Spinal Sensory and Motor Neurons
Published on: April 18, 2017
Related Concept Videos
Classification of Skeletal Muscle Relaxants
Peripherally acting skeletal muscle relaxants interfere with the neurotransmission at the neuromuscular end plate to induce paralysis during...
Nondepolarizing (Competitive) Neuromuscular Blockers: Mechanism of Action
Competitive antagonists prevent acetylcholine from binding to its receptor, inhibiting membrane depolarization. Without conformational changes or intrinsic...
Nondepolarizing (Competitive) Neuromuscular Blockers: Pharmacological Actions
Although all competitive neuromuscular blockers are designed...
Nondepolarizing (Competitive) Neuromuscular Blockers: Pharmacokinetics
Instead, they are transported by the blood to different tissues. Muscles with a greater blood supply (arteries) and blood flow receive more...
Depolarizing Blockers: Mechanism of Action
Succinylcholine is the most commonly used depolarizing blocker. Chemically, it constitutes two molecules of acetylcholine joined together by an acetate methyl group. They act on the receptors in the same way as acetylcholine. Because succinylcholine...
Depolarizing Blockers: Pharmocokinetics