Excitation of Limulus Photoreceptors by Hydrolysis-Resistant Analogs of cGMP and cAMP

Authors

Jane M. Feng, University of Connecticut
Tamara M. Frank, University of ConnecticutFollow
Alan Fein, University of Connecticut

ORCID

0000-0002-9329-2414

Document Type

Article

Publication Title

Brain Research

ISSN

0006-8993

Publication Date

6-28-1991

Keywords

Limulus polyphemus, Photoreceptor, Cyclic guanosine 5′-phosphate, Cyclic adenosine 5′-phosphate

Abstract

cGMP was proposed to be the agent which directly opens the light-sensitive channel in Limulus ventral photoreceptors. However, the light-sensitive rhabdomeral-lobe (R-lobe) is not uniformly responsive to cGMP injection; that is, there are ‘hot spots’ of sensitivity. A potent phosphodiesterase which rapidly hydrolyses cGMP was suggested to explain the existence of these ‘hot spots’. To test this idea we injected ventral photoreceptors with hydrolysis-resistant cyclic nucleotide analogues. Whereas there can be a lack of a response to cGMP injection into the R-lobe, we find a reproducible depolarization upon R-lobe injection of hydrolysis-resistant cGMP analogues. Furthermore, the depolarization resulting from the injection of cGMP analogues does not require a rise in intracellular Ca²⁺, as it is not blocked by the Ca²⁺ buffer, BAPTA. Surprisingly, R-lobe injection of a hydrolysis-resistant cAMP analogue also depolarized ventral photoreceptors. Further work will be needed to resolve the role of cGMP in Limulus visual transduction.

DOI

10.1016/0006-8993(91)90094-C

Volume

552

Issue

2

First Page

291

Last Page

294

Comments

©1991 Published by Elsevier B.V.

NSUWorks Citation

Jane M. Feng, Tamara M. Frank, and Alan Fein. 1991. Excitation of Limulus Photoreceptors by Hydrolysis-Resistant Analogs of cGMP and cAMP .Brain Research , (2) : 291 -294. https://nsuworks.nova.edu/occ_facarticles/766.