“…The following bioactive substances have been found in the NEE cells, as well as the NEBs, of amphibians: serotonin (5‐hydroxytriptamine; Cutz et al ., 1986; Scheuermann et al ., 1989; Goniakowska‐Witalinska et al ., 1992), bombesin (Cutz et al ., 1986; Gomi et al ., 1994), enkephalin (Goniakowska‐Witalinska et al ., 1992), substance P (SP; Adriaensen & Scheuermann, 1993), somatostatin (Gomi et al ., 1994), calcitonin (Gomi et al ., 1994), calcitonin gene‐related peptide (CGRP; Gomi et al ., 1994) and neuron‐specific enolase (Gomi et al ., 1994). Serotonin was detected in a larger number of NEE cells than any other bioactive substance in the salamanders (Scheuermann et al ., 1989; Gomi et al ., 1994).…”