title: Morphological and physiological characteristics of dermal photoreceptors in Lymnaea stagnalis.
abstract: Dermal photoreceptors located in the mantle of Lymnaea stagnalis were histologically and physiologically characterized. Our previous study demonstrated that the shadow response from dermal photoreceptors induces the whole-body withdrawal response. Through the interneuron, RPeD11, we detected that the light-off response indirectly originated from a dermal photoreceptor. Previous observations, based on behavioral pharmacology, revealed that cyclic guanosine monophosphate acts as a second messenger in the dermal photoreceptor. Furthermore, gastropods possess dermal photoreceptors containing rhodopsin, as a photopigment, and another photo-sensitive protein, arrestin, responsible for terminating the light response. Thus, we chose three antibodies, anti-cGMP, anti-rhodopsin, and anti-β-arrestin, to identify the dermal photoreceptor molecules in Lymnaea mantle. Extracellular recording, using a suction electrode on the mantle, revealed a light off-response from the right parietal nerve. Overlapping structures, positive against each of the antibodies, were also observed. Numerous round, granular particles of 3-47 μm in diameter with one nucleus were distributed around pneumostome and/or inside the mantle. The cells surrounding the pneumostome area, located 10 μm beneath the surface, tended to have smaller cell soma ranging from 3 to 25 μm in diameter, while cells located in other areas were distributed uniformly inside the mantle, with a larger diameter ranging from 12 to 47 μm. The histological examination using back-filing Lucifer Yellow staining of the right parietal nerve with the three dermal photoreceptor antibodies confirmed that these overlapping-stained structures were dermal photoreceptors in Lymnaea.
authors: Graduate School of High-Technology for Human Welfare, Tokai University, Numazu, Shizuoka 410-0321, Japan; Graduate School of Bioscience, Tokai University, Numazu, Shizuoka 410-0321, Japan.
authors: Satoshi
authors: S
authors: Takigami
authors: Hotchkiss Brain Institute, Faculty of Medicine, University of Calgary, Calgary, AB T2N 4N1, Canada.
authors: Hiroshi
authors: H
authors: Sunada
authors: Graduate School of High-Technology for Human Welfare, Tokai University, Numazu, Shizuoka 410-0321, Japan; Graduate School of Bioscience, Tokai University, Numazu, Shizuoka 410-0321, Japan; School of Engineering, Department of Biomedical Engineering, Tokai University, Hiratsuka, Kanagawa 259-1292, Japan.
authors: Tetsuro
authors: T
authors: Horikoshi
authors: Graduate School of High-Technology for Human Welfare, Tokai University, Numazu, Shizuoka 410-0321, Japan; Graduate School of Bioscience, Tokai University, Numazu, Shizuoka 410-0321, Japan; School of High-Technology for Human Welfare, Tokai University, Numazu, Shizuoka 410-0321, Japan.
authors: Manabu
authors: M
authors: Sakakibara
keywords: cGMP; electrophysiology; extracellular recording; immunohistochemistry; rhodopsin; β arrestin