| The mucous cells (MC) of traíra, Hoplias malabaricus, and jeju, Hoplerythrinus unitaeniatus, two ecologically distinct erythrinid species, were analyzed in fish exposed to deionized (DW) and high ion concentration (NaCl and Ca2+) water (HIW) during 15 days to evaluate the MC responses to ion challenge. MCs are localized in the leading and trailing edge and, interlamellar region of the gill filament epithelium but, in H. unitaeniatus, they are also found in the breathing or lamellar epithelium. MC density is lower in H. malabaricus, the exclusively water-breathing fish, than in H. unitaeniatus, a facultative air-breathing fish. The transference to DW or HIW did not change the MC density and surface area, excepting in H. malabaricus, in the first day of... |
