Intracellular potentials of microperfused human sweat duct cells

Intracellular potentials of cells from isolated segments of microperfused human sweat ducts were measured in order to determine the electrical profiles of these cells under resting, transporting, and inhibited conditions. Even though the cells are relatively small (ca. 6-8 microns), continuous recordings of intracellular potentials from the same impalement were stable for up to 2 h. In the resting condition in normal Ringer's solution when the lumen of the duct was collapsed and not perfused, the intracellular potential measured across the basal membrane was 34.6 +/- 1.5 mV (n = 31; mean +/- SE). In the same bathing medium, when the duct lumen was also perfused with normal Ringer's solution, the basolateral membrane potential (Vb), the apical membrane potential (Va) and transepithelial potential (Vt) was -33.8 +/- 0.47 mV, -23.7 +/- 0.48 mV and -9.6 +/- 0.9 mV (n = 73), respectively. The average input impedence (Ri) of these cells was 19.6 +/- 0.4 M omega (n = 36). The frequency distribution of Vb was unimodal suggesting that only one functional cell type exists in this tissue. Amiloride (0.1 mM) in the lumen hyperpolarized both Va and Vb by -40.5 +/- 3.6 mV and -33.2 +/- 3.7 mV (n = 15), respectively, with a slight but significant increase in Ri(15%) while abolishing Vt. Removing luminal Cl- depolarized Va by +37.0 +/- 4.2 mV and hyperpolarized Vb by -19.0 +/- 4.2 mV (n = 11). Removing Cl- from the bath hyperpolarized Va by -3.3 +/- 2.3 mV and depolarized Vb by +24.3 +/- 2.7 mV (n = 15).(ABSTRACT TRUNCATED AT 250 WORDS)