My story has vampires in it. Within my story's universe, I want a human kissing one mouth-to-mouth to result in nitrogen narcosis-like symptoms for said human, and for said symptoms to intensify as long as the kiss is maintained.
For reference: nitrogen narcosis is caused by inhaling nitrogen gas at a high pressure. As the pressure increases, the victim - among several other symptoms - slowly looses their consciousness and ability to think clearly, up until they pass out and/or die.
Unfortunately, nitrogen narcosis won't work as an explanation for this, since I want to write a somewhat biologically plausible vampire. A form of life that's...
- compatible with Earthly biology
- contains nitrogen gas under many atmospheres of pressure - for instance, to be lethal, the nitrogen gas's pressure has to exceed at least 10 atmospheres -
...doesn't seem remotely (let alone "somewhat") plausible to me. Moreover, I don't think releasing a gas at 10 atmospheres of pressure within kissing range of a human - and doing under sea-level atmospheric conditions - would be safe for said human.
What biological mechanism would cause a kiss with a vampire to - as long as the kiss is held - slowly afflict the other participant with symptoms of nitrogen narcosis, and how can such a thing work without being incompatible with Earthly biology?
The nitrogen narcosis-like effect needs to wear off over a week at most and half a minute at least.
Acceptable answers can be anything that could possibly exist within the limits of Earth-based biochemistry, but please don't make ones based on non-biological technology or magic - these vampires were bioengineered, not cybernetically altered or summoned from Hell.
Good answers will be biologically plausible, or at least not cite things like "magical knockout gas".
Better answers will cite a specific biological mechanism, and why the answerer believes said mechanism will mimic the effects of nitrogen narcosis.
The best answers will do all of the above, as well as specifically explain the pathophysiology of how their mechanism slowly shuts down the human brain. For instance, such an explanation for nitrogen narcosis would state that it
appears to be the direct effect of gas dissolving into nerve membranes and causing temporary disruption in nerve transmissions.