Transmitter and peptide systems in areas involved in the control of blood pressure

The distribution of catecholamine neurons in the dorsal vagal complex is described on the basis of indirect immunofluorescence histochemistry using antisera to three enzymes in the catecholamine synthesis, tyrosine hydroxylase, dopamine-beta-hydroxylase and phenylethanolamine-N-methyltransferase, allowing differentiation between dopamine, noradrenaline and adrenaline cells. In addition attention was focused on the occurrence of two peptides, neuropeptide Y (NPY) and neurotensin in this region. It could be established that they partly were present in subpopulations of the A2/C2 catecholamine neurons. The significance of this coexistence of a peptide and a catecholamine is discussed.