GABAAreceptor activation

Activation of GABAAreceptor benzodiazepine binding site causes ↑ chloride influx

Possible activation of Ca M – N O S- cG M P-PKG pathway (exact mechanism unknown)

Anxiolysis
Myeloneuropathy
Encephalopathy
Subacute Combined Degeneration of spinal cord
Peripheral Neuropathy
Hyperhomocysteinemia

Megaloblastic Anemia

Irreversible inhibition of methionine synthase

Modulation of nociception

Stimulation of neurons in PAG of midbrain causes release of E O Ps and/or DY N s

Activation of opioid receptors in GABA-ergicnuclei of pons causes inhibition of inhibitory GABA-ergicpathway

Activation of descending noradrenergic system in spinal cord posterior grey column

Inhibition of primary afferent and second-order neuron nociception

Analgesia
Authors: Parthiv Amin Reviewers: Billy Sun Joseph Tropiano Michael Chong* * MD at time of publication

Abbreviations •CaM-calmodulin •cGMP-cyclic guanosine monophosphate •DYN-dynorphin •EOP-endogenous opioid peptide •GABA-γ-aminobutyric acid •N2O-nitrous oxide •NDMA-N-methyl-D-aspartate •NOS-nitric oxide synthase •PAG-periaqueductal grey area •PKG-protein kinase
Nitrous Oxide
NDMA receptor antagonism: Inhibition of the N D M A glutamate receptor

Closure of NDMA receptor channel

Inhibition of ionic currents

↓ central nervous system excitability

Anesthesia

Quick Facts
1°Use: Anesthesia Adjuvant 2°Use: Analgesia, Dental Sedation, Anxiolytic
Route of Admin.: Inhalation Metabolism: None Excretion: 1°=Lung (exhalation)
Min. Alveolar Conc.: >100% @1atm = Incomplete Anesthetic
Vitamin B12 Inactivation: N2O irreversibly oxidizes Vitamin B12 (cobalamin)

Pyramidal Cell Vacuole Reaction: Swelling of endoplasmic reticulum and mitochondria
Reversible pyramidal cell neurotoxic vacuole reaction in posterior cingulate / retrosplenial cortex
Neurotoxicity
Legend:
Pathophysiology
Mechanism
Sign/Symptom/Lab Finding
Complications
Published January,07, 2018 on www.thecalgaryguide.com