Trace Amine-Peptide Interactions on Central Neurones: I. Tryptamine and Substance P.

Abstract

Much attention is being paid to the recent observations of co-existence of amines and peptides in neurones in several areas of the CNS and possible implications of functional interactions of two transmitters released from the same neurone The existence of a descending spinal pathway containing 5-hydroxytryptamine(5HT) and substance P (SP) is now established(Hokfelt et al.,1978) and it has been demonstrated recently that 5HT is occlusive to the effects of SP on dorsal horn interneurones (Davies and Roberts,1981). Although it is not known whether 5HT and SP co-exist in ascending pathways this appears possible (Savard et al.,1982) and the present study has investigated the interactions of 5HT with SP on single neurones in the anterior cingulate cortex. In view of the probable existence of a raphe-cortica1 pathway containing tryptamine (T) (see Jones, 1982) the interactions between this amine and SP were also investigated.