Ketamine physiological effects

Ketamine exerts its physiological effects at the molecular level by interfering with the actions of excitatory amino acid neurotransmitters, primarily glutamate, the most prevalent excitatory neurotransmitter in the brain. The excitatory neurotransmitters regulate numerous functions of the central nervous system. 

Intravenous anesthetics produce a narrower range of physiological effects, predominantly at the synapse, where they have profound and relatively specific effects on the postsynaptic response to released neurotransmitter. Most of the intravenous agents act predominantly by enhancing inhibitory neurotransmission, whereas ketamine predominantly inhibits excitatory neurotransmission at glutamatergic syncq)ses. 

The ion-channel blocking mechanism has been widely tested and found to be important in both pharmacology and physiology. Examples are the block of nerve and cardiac sodium channels by local anesthetics, or block of NMDA receptor channels by Mg2+ and the anesthetic ketamine. The channel-block mechanism was first used quantitatively to describe block of the squid axon K+ current by tetraethylammonium (TEA) ions. The effects of channel blockers on synaptic potentials and synaptic currents were investigated, particularly at the neuromuscular junction, and the development of the single-channel recording technique allowed channel blockages to be observed directly for the first time. 

Schatzmann U, Armbruster S, Stucki F et al 2001 Analgesic effect of butorphanol and levomethadone in detomidine sedated horses. Journal of Veterinary Medicine A Physiology, Pathology, Clinical Medicine 48 337-342 Schwedler M, Miletich D J, Albrecht R F 1982 Cerebral blood flow and metabolism following ketamine administration. Canadian Anaesthetists Society Journal 29 222-226... 

Albrecht M, Henke J, Tacke S, Marker M, Guth B (2014) Effects of isoflurane, ketamine-xylazine and a combination of medetomidine, midazolam and fentanyl on physiological variables continuously measured by telemetry in Wistar rats. BMC Vet Res 10 198... 

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