368회 Amphibian pheromonal systems and their application for the toxico…

368회

연사 :  박 대 식, 강원대학교 사범대학 과학교육학부

제목:  Amphibian pheromonal systems and their application for the toxicological study of environmental chemicals

Abstract

 Olfaction is probably the most ancient of the organized senses and plays a critical role in the daily life of vertebrates. To increase mating success when the operational sex ratio is male-biased, an actively courting male may utilize specific mechanisms that prevent an increase in male-male competition within his courting group. One way to minimize the sex ratio within a courting group is to use chemical cues that function to repel conspecific males that may otherwise approach towards the courting group. There were no reports of a pheromonal repelling response in vertebrates. I have found a proteinaceous pheromone of approximately 33 kDa secreted from the cloacal glands of male red-spotted newts, Notophthalmus viridescens. This pheromone, in conjunction with female odors, repels conspecific males by acting primarily through the vomeronasal system. This is the first report of a pheromonal repelling response in vertebrates.

   Using basic knowledge about amphibian pheromonal systems, I have also determined whether amphibian pheromonal systems can be developed as model systems to detect subtle negative effects of environmental chemicals that may be involved in the recently documented global decline of amphibian populations. Both male and female red-spotted newts were exposed to low doses of a commonly used insecticide, endosulfan. Through behavioral, histomorphometric, hormonal, and electrophysiological studies I found that amphibian pheromonal and olfactory systems are highly vulnerable to disruption following exposure to environmental chemicals. Disruption of the pheromonal system resulted in lowered individual interactions, failed mate attraction, and consequently decreased mating success. These results suggest that amphibian pheromonal systems are subject to subtle negative effects of environmental chemicals.