Evidence for the Lack of By-Pass Shunting in Teleost Gills

Abstract

Retention of 15 μ diameter tracer-labelled microspheres in the gills was studied in some Alaskan teleosts. Neither adrenaline nor acetylcholine significantly affected the percentage retention, as predicted by earlier reports on by-pass shunts affected by these drugs. Rentention of 50 μ microspheres was nearly complete, even under conditions reported to favor shunting. Histological examination of microsphere-treated gills revealed no accumulation in the reported shunt pathways under any conditions. If the shunts do exist, their significance would seem to be slight.