Electrophysiological responses of frog skin to the peptides bombesin, caerulein, and physalaemin.
Isolated skins from the frog Rana pipiens were mounted on Ussing-type chambers and bathed with Amphibian Ringer's solution on both sides. Electrical potential difference, resistance, and short-circuit current (SCC) were measured by using calomel electrodes, Ag-AgCl electrodes, Ringer's-agar bridges, and Tektronix digital multimeters. Under the conditions employed, SCC is a measure of net Na+ transport. The frog skin peptides bombesin, caerulein, and physalaemin were administered to the serosal side at concentrations of 0.5, 5.0, and 50 ng/ml. Control electrophysiological parameters were: potential difference, 23 +/- 2 mV; resistance, 738 +/- 59 ohms cm2; and SCC 32 +/- 3 microA/cm2. Although bombesin and caerulein had no significant, reversible effect on potential difference, resistance, or SCC, physalaemin significantly, and reversibly, depressed SCC by 22%. Caerulein did significantly depress SCC, but the response was not reversible.
Stiffler
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DF
Biological Sciences Department, California State Polytechnic University, Pomona 91768, USA. dfstiffler@csupomona.edu
D000818:Animals; D001839:Bombesin / Q000494:pharmacology*; D002108:Ceruletide / Q000494:pharmacology*; D004594:Electrophysiology; D066298:In Vitro Techniques; D010803:Physalaemin / Q000494:pharmacology*; D011894:Rana pipiens; D012879:Skin Physiological Phenomena / Q000187:drug effects*
D010803:Physalaemin; D002108:Ceruletide; D001839:Bombesin