SENSORY AND NEUROSECRETORY INNERVATION OF LEECH NEPHRIDIA IS ACCOMPLISHED BY A SINGLE NEURON CONTAINING FMRFAMIDE

The neural control of the excretory system of the medicinal leech Hiru do medicinalis has been characterized morphologically and chemically u sing light and electron microscopy, immunocytochemistry and biochemist ry. Immunoreactivity against RFamide-like peptides revealed elaborate neuronal aborizations of a neurone in the nephridium, around the urina ry bladder sphincter and in the central nervous system. The processes arose from the nephridial nerve cell (NNC), a previously identified re ceptor neurone. Using a combination of reverse-phase high pressure liq uid chromatography, radioimmunoassay and subsequent Edman degradation and mass spectrometry, authentic FMRFamide has been identified as the major peptide of the NNC. Sensory and neurosecretory innervation of th e nephridia is thus accomplished by a single neurone, which is thought to modulate nephridial performance.