Peptidergic synaptic transmission in sympathetic ganglia.

Biologically active peptides have been localized in neuronal cell bodies, axons, and synaptic boutons of sympathetic ganglia; some of these peptides may be neurotransmitters. For example, substances immunologically similar to substance P and luteinizing hormone-releasing hormone appear to be released from nerve terminals in sympathetic ganglia. In each case, the postsynaptic action of the peptide lasts for several minutes and is accompanied by a combination of decreases and increases in the membrane conductance that are voltage dependent. These peripheral peptidergic synapses may be models for peptidergic transmission in the central nervous system where detailed analysis is more difficult.