[Diving: barometric pressure and neurochemical mechanisms].
The studies of Paul Bert, presented in his book "La Pression Barométrique" in 1878, were at the origin of the modern hyperbaric physiology. Indeed his research demonstrated the effects of oxygen at high pressure, that compression effects must be dissociated from decompression effects, and that neurological troubles and death of divers during or after decompression were due to the fast rate of decompression. However, it is only in 1935 that the work of Behnke et al. attributed the complaints reported at 3 bars and above in compressed air or nitrogen-oxygen mixture to the increase in partial pressure of nitrogen which induces nitrogen narcosis. Little is known about the origins and mechanisms of this narcosis. The traditional view was that anaesthesia or narcosis occurred when the volume of a hydrophobic membrane site was caused to expand beyond a critical amount by the absorption of molecules of a narcotic gas. The observation of the pressure reversal effect during general anaesthesia has long supported this lipid theory. However, recently, protein theories have met with increasing recognition since results with gaseous anaesthetics have been interpreted as evidence for a direct gas-protein interaction. The question is to know whether inert gases, that disrupt dopamine and GABA neurotransmissions and probably glutamatergic neurotransmission, act by binding to neurotransmitter protein receptors.
Rostain
Jean-Claude
JC
Université de la Méditerranée, Institut de Médecine Navale du Service de Santé des Armées EA3280, Physiopathologie et Action Thérapeutique des Gaz sous Pression, IFR Jean Roche, Faculté de Médecine Nord, Marseille, France. rostain.jc@jean-roche.univ-mrs.fr
Balon
Norbert
N
D000769:Anesthesia, Inhalation; D018685:Anesthetics, Inhalation / Q000009:adverse effects* / Q000493:pharmacokinetics; D001274:Atmospheric Pressure; D017704:Baroreflex / Q000502:physiology*; D001921:Brain / Q000187:drug effects / Q000503:physiopathology; D002463:Cell Membrane Permeability; D003665:Decompression Sickness / Q000266:history* / Q000503:physiopathology; D004242:Diving / Q000009:adverse effects; D005602:France; D006371:Helium / Q000008:administration & dosage / Q000009:adverse effects; D006610:High Pressure Neurological Syndrome / Q000209:etiology / Q000266:history* / Q000503:physiopathology; D049672:History, 19th Century; D006801:Humans; D006859:Hydrogen / Q000008:administration & dosage / Q000009:adverse effects; D007222:Inert Gas Narcosis / Q000209:etiology / Q000266:history* / Q000503:physiopathology; D008959:Models, Neurological; D009356:Neon / Q000008:administration & dosage / Q000009:adverse effects; D018377:Neurotransmitter Agents / Q000378:metabolism; D009584:Nitrogen / Q000008:administration & dosage / Q000009:adverse effects; D010100:Oxygen / Q000008:administration & dosage / Q000502:physiology; D010313:Partial Pressure; D011312:Pressure; D011963:Receptors, GABA-A / Q000187:drug effects / Q000502:physiology; D009435:Synaptic Transmission / Q000187:drug effects; D012122:Ventilators, Mechanical
D018685:Anesthetics, Inhalation; D018377:Neurotransmitter Agents; D011963:Receptors, GABA-A; D006371:Helium; D009356:Neon; D006859:Hydrogen; D009584:Nitrogen; D010100:Oxygen