from the article:
"During the 1950s and 1960s, the primary mechanisms proposed were alterations in blood pH and inhibition of neuronal function by the slowing of cellular metabolism. More recent research paints a complex picture of interconnected systems, including activation of serotonin (5-HT) neurons in the raphe nuclei (located in the mid-brain) where most serotonin neurons have their cell bodies.18,19,20"
and...."Carbon dioxide dissolved in blood is acidic, just as it is in carbonated soda. Inhalation of carbogen rapidly increases acidity (lowers pH) of the blood, cerebrospinal fluid, and brain, creating a condition called respiratory acidosis or hypercapnia. In 1938 Gibbs and Gibbs repeatedly measured arterial and venous blood pH while administering a 35-breath session with Meduna's mixture. They found that arterial blood pH dropped from 7.37 at the start of the session to 6.94 after 35 inhalations,17 a level that could be dangerous if maintained for prolonged periods. Blood pH rapidly returns to normal after carbogen administration ends. Although many researchers believe that lowered pH directly causes reduced brain activity and anaesthesia,22,23 acidosis alone probably does not explain carbogen's visual and visionary effects."
"nterestingly, high levels of carbon dioxide also lead to rapid dilatation of cerebral vessels and increased cerebral blood flow.23,24 For brief periods, increases in blood flow in the brain are generally associated with improvements in cognitive performance."
finally-
"Recent advances in understanding the identity and location of the brain's carbon dioxide chemoreceptors may provide better explanations for the anxiogenic and visionary effects of carbogen. Over the last decade, a number of researchers have verified that a subset of serotonin neurons in the raphe nuclei respond to hypercapnia.18 Because of the many brain areas to which they extend, such serotonin neurons are well-placed to not only trigger autonomic responses, such as breath and cerebral blood flow, but also interact with the parts of the brain responsible for cognition and emotions"
I think this bears investigation. Perhaps if I get time in my hectic existence I can try it soon.....I'm very curious.
I remember when I was an employee in a restaraunt as a teenager and I took a breath out of a baloon I thought was filled with helium, it was actually filled with CO2, and I took one deep breath and fell down, nearly unconscious...I knew very little about drugs or chemicals and it scared the hell out of me.
But I am intrigued.....
