Abstract
Microspectrophotometrically derived difference spectra from the barnacles Balanus amphitrite and B. eburneus show that a blue illumination after an orange illumination causes a decrease in absorption in the blue region and an increase in absorption in the green-yellow region, with an isosbestic point around 535 nm. Orange- following-blue illumination causes the reverse changes. The dark time between the adapting and measuring lights has no influence on the data. The results confirm previously reported ERP measurements which indicate that the barnacle visual pigment has two photointerconvertible dark- stable states. If one assumes a Dartnall nomogram shape for the two absorption spectra, a best fit to the observed difference spectra is obtained with nomograms peaking at 492 nm and 532 nm, with a peak absorbance ratio around 1.6:1. These two nomograms fit very well the ERP action spectra of metarhodopsin and rhodopsin, respectively, thus indicating that the ERP is a reliable measure of visual-pigment changes in the barnacle. The existence of a photostable blue pigment is demonstrated in B. eburneus and in some of B. amphitrite receptors, and the possible influence of this photostable pigment on the various action spectra measured in the barnacle is discussed.
Full Text
The Full Text of this article is available as a PDF (585.1 KB).
Selected References
These references are in PubMed. This may not be the complete list of references from this article.
- Brown H. M., Cornwall M. C. Spectral correlates of a quasi-stable depolarization in barnacle photoreceptor following red light. J Physiol. 1975 Jul;248(3):555–578. doi: 10.1113/jphysiol.1975.sp010988. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Hillman P., Hochstein S., Minke B. A visual pigment with two physiologically active stable states. Science. 1972 Mar 31;175(4029):1486–1488. doi: 10.1126/science.175.4029.1486. [DOI] [PubMed] [Google Scholar]
- Kirschfeld K., Franceschini N., Minke B. Evidence for a sensitising pigment in fly photoreceptors. Nature. 1977 Sep 29;269(5627):386–390. doi: 10.1038/269386a0. [DOI] [PubMed] [Google Scholar]
- Kirschfeld K., Franceschini N. Photostable pigments within the membrane of photoreceptors and their possible role. Biophys Struct Mech. 1977 Jun 29;3(2):191–194. doi: 10.1007/BF00535818. [DOI] [PubMed] [Google Scholar]
- Minke B., Hochstein S., Hillman P. Early receptor potential evidence for the existence of two thermally stable states in the barnacle visual pigment. J Gen Physiol. 1973 Jul;62(1):87–104. doi: 10.1085/jgp.62.1.87. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Minke B., Hochstein S., Hillman P. Letter: Antagonistic process as source of visible-light suppression of afterpotential in Limulus UV photoreceptors. J Gen Physiol. 1973 Dec;62(6):787–791. doi: 10.1085/jgp.62.6.787. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Shaw S. R. Decremental conduction of the visual signal in barnacle lateral eye. J Physiol. 1972 Jan;220(1):145–175. doi: 10.1113/jphysiol.1972.sp009699. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Stratten W. P., Ogden T. E. Spectral sensitivity of the barnacle, Balanus amphitrite. J Gen Physiol. 1971 Apr;57(4):435–447. doi: 10.1085/jgp.57.4.435. [DOI] [PMC free article] [PubMed] [Google Scholar]