Responsiveness of vomeronasal cells to a newt peptide pheromone, sodefrin as monitored by changes of intracellular calcium concentrations

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• 作者：Takeo Iwata ; Tomoaki Nakada ; Fumiyo Toyoda ; Toshihiko Yada ; Seiji Shioda ; Sakae Kikuyama
• 关键词：[Ca2+]i ; intracellular concentrations of Ca2+ ; CalC ; calphostin C ; DAG ; diacylglycerol ; E2 ; estradiol ; EOG ; electro-olfactogram ; ER ; endoplasmic reticulum ; F340/F380 ; ratio of fluorescence intensity excited at 340  ; nm and 380  ; nm ; HBSS ; HEPES buff
• 刊名：Peptides
• 出版年：2013
• 出版时间：July, 2013
• 年：2013
• 卷：45
• 期：Complete
• 页码：15-21
• 全文大小：1433 K

文摘

A peptide pheromone of the red-bellied male newt, sodefrin was tested for its ability to increase intracellular concentrations of Ca²⁺ ([Ca²⁺]_i) in the dissociated vomeronasal (VN) cells of females by means of calcium imaging system. The pheromone elicited a marked elevation of [Ca²⁺]_i in a small population of VN cells from sexually developed females. The population of cells exhibiting sodefrin-induced elevation of [Ca²⁺]_i increased concentration-dependently. A pheromone of a different species was ineffective in this respect. The VN cells from non-reproductive females or from reproductive males scarcely responded to sodefrin in terms of elevating [Ca²⁺]_i. In the cells from hypophysectomized and ovariectomized females, the sodefrin-inducible increase of [Ca²⁺]_i never occurred. The cells from the operated newts supplemented with prolactin and estradiol exhibited [Ca²⁺]_i responses to sodefrin with a high incidence. Thus, sex- and hormone-dependency as well as species-specificity of the responsiveness of the VN cells to sodefrin was evidenced at the cellular level. Subsequently, possibility of involvement of phospholipase C (PLC)-inositol 1,4,5-trisphosphate (IP₃) and/or PLC-diacylglycerol (DAG)-protein kinase C (PKC) pathways in increasing [Ca²⁺]_i in VN cells in response to sodefrin was explored using pharmacological approaches. The results indicated that PLC is involved in generating the Ca²⁺ signal in all sodefrin-responsive VN cells, whereas IP₃ in approximately 50 % of the cells and DAG-PKC in the remaining cells. In the latter case, the increase of [Ca²⁺]_i was postulated to be induced by the influx of Ca²⁺ through the L-type channel. The significance of the finding is discussed.