ELECTRICAL-PROPERTIES OF THE ISOLATED, IN-VITRO PERFUSED MALPIGHIAN TUBULE OF THE ANT, THE CL- PATHWAY

An electrical characterization of the isolated, perfused malpighian tubule of Formica polyctena and F. rufa is reported. Some specific problems of the perfusion method as applied to malpighian tubules of the ant are discussed and a practical solution presented. Estimates for the individual membrane resistances are derived. The shunt is investigated by basolateral biionic replacements and found to be anion specific. The Cl- pathway is further investigated by the addition of Cl- channel blockers, 5-nitro-2-(3-phenylpropylamino)-benzoate (NPPB) and 4,4'-diisothiocyano-2,2'-stilbenedisulfonate (DIDS), to the lumen. The lack of effect suggests the absence of DIDS- and NPPB-sensitive Cl- channels.