ABSTRACT
This chapter seeks to provide the reader some information on how to assay for particular two classes of neurotransmitters and neurotransmitter enzymes. The catecholamines are a group of biogenic amines which act as neurotransmitters. This group includes: dopamine, norepinephrine, and epinephrine. Tyrosine Hydroxylase (TH) is the rate limiting enzyme in the biosynthesis of the catecholamines. There are several ways in which TH can be assayed. There are many other enzymes that are involved in the metabolism of various neurotransmitters. The enzyme responsible for the synthesis of acetylcholine is choline acetyltransferase. The acetylcholine analog, acetylthiocholine, has been used for histochemical localization, for enzyme assays and for inhibition studies. If enzyme activities are low, it may be possible to increase the sensitivity of the assay by extracting the water layer a second time with the ethylbutyl ketone-Kalignost solution. This will remove more radioactive acetylcholine, decreasing the background radioactivity and increasing sensitivity.
