Detection and characterisation of neurotransmitters, particularly peptides, in the gastrointestinal tract

Abstract

There are now about twelve substances, many of them peptides, that are thought to act as neurotransmitters in the enteric nervous system. Most of the studies of peptides have relied on immunochemical methods for their detection. However, difficulties arise in these studies because of the close similarities between peptides. Related peptides can be grouped in several ways according to similarities of origin, function, effects in bioassays and amino acid sequences. Peptides with the same function in different species, and only slight differences in amino acid sequences, have been called isopeptides. Peptide families that have sequences of amino acids in common, but do not necessarily have simi..