TAURINE-LIKE IMMUNOREACTIVITY IN THE MOTOR-NERVE NET OF THE JELLYFISHCYANEA-CAPILLATA

Two antisera against the sulfonated amino acid taurine were applied to subumbrella tissue of the jellyfish Cyanea capillata. Taurine-immunor eactive nerve nets were found in both the ectoderm and endoderm. The e ctoderm had two morphologically and immunocytochemically distinct popu lations of neurons, the motor nerve net (MNN), which was immunoreactiv e to the taurine-like molecule, and the diffuse nerve net (DNN), which was immunoreactive to the neuropeptide Phe-Met-Arg-Phe-NH2 (FMRFamide ). In the endoderm, immunoreactivity was found in the endodermal DNN. This localization was confirmed by double-labeling experiments, which also revealed that the endodermal DNN neurons may contain both taurine and FMRFamide-related peptide. The presence of a taurine immunoreacti vity in the MNN supports the hypothesis that taurine or some chemicall y related compound is the neurotransmitter at synapses within the MNN of Cyanea.