First of, acethylcholine (ACh) does NOT contain chlorine. This neurotransmitter is an amine that exerts it's function first and foremost in neuromuscular functions, aside from that it also works on different places in the central and peripheral nervous system. The amine is created from acetyl co-enzyme A (acetyl CoA) and choline. Transfer of an acetyl group from acetyl CoA to the choline by the enzymatic reaction catalysed by coline acetyltranferase. Antagonists of ACh are curare (the substance used by indians to paralyze their prey when hunting) and atropine (derived from the Belladonna plants, used in small amounts in Spain to give women dilated pupils, which was considered a sign of beauty). It is unlikely that ACh is used by the body itself to increase aggressional tendancies, a trait which is ascribed mostly to the hormone testosterone. Tensile strength in the muscle will be increased, however, as the knowledge is anno 2006, no aggresive behaviour is ascribed to increased ACh levels.
As much as Star Trek implies to contain accurate medical knowledge, lot's of it is based on fiction. Perhaps interspecies differences are responsible, and paramount/the writers of the scripts will always find a way to discredit arguments given against the knowledge portrait in ST as real. I'm not writing this to start a riot or discredit ST in general, since I love the series and wish to see much much more of it regardless of accurate medical knowledge. HOWEVER, I'd like to stress, the information on the internet given by sites such as this SHOULD contain accurate information, or it SHOULD have a mention of the possible interspecies differences accompanying the text. I'd like to stress updating this information to give the most accurate information present today, with a mention of possible differences in the 24th century, just for the sake of scientific integrity. Sincerely, Heatcliff Life-Science & Technology student from Holland