Intracellular injections of BAPTA block induction of enhancement in Hermissenda type B-photoreceptors.
Light paired with serotonin (5-HT) in vivo produces both short- and long-term enhancement of generator potentials in identified B-photoreceptors in Hermissenda. The role of intracellular Ca2+ in the induction of enhancement in B-photoreceptors was assessed by buffering intracellular Ca2+ with the iontophoretic injection of BAPTA. Blocking light-elicited photoreceptor desensitization with BAPTA loading prior to applying 5-HT was used as an indication of the effectiveness of Ca2+ buffering. Enhancement was blocked in preparations that received BAPTA loading prior to the application of 5-HT while typical enhancement was elicited by light and 5-HT in control preparations. These results indicate that enhancement involves a Ca(2+)-dependent process.
Falk-Vairant
J
J
Department of Neurobiology and Anatomy, University of Texas Medical School, Houston 77225.
Crow
T
T
D000818:Animals; D003386:Brachyura / Q000502:physiology*; D004533:Egtazic Acid / Q000031:analogs & derivatives* / Q000494:pharmacology; D004594:Electrophysiology; D007478:Iontophoresis; D008027:Light; D010775:Photic Stimulation; D010786:Photoreceptor Cells / Q000187:drug effects*; D012623:Seawater
D004533:Egtazic Acid; C025603:1,2-bis(2-aminophenoxy)ethane-N,N,N',N'-tetraacetic acid