Pheromones are chemical molecules that are released by certain individuals of an animal species and that induce changes of behavior, physiology or development in other individuals of the same species. Pheromones that induce behavioral changes have received most attention. One such example can be found in the sea lamprey (Petromyzon marinus), an ancestral jawless fish. It is well documented that sexually mature male sea lampreys release some bile acids that attract sexually mature female sea lampreys to mating sites. Recently, further research has indicated that these bile acids may also induce less mature sea lampreys to mature faster. In this study, it is hypothesized that the bile acid pheromone signals are transmitted from the olfactory organ (nose) to the hypothalamus (a part of the central nervous system with a role in regulation of reproduction) to induce an increase in the production and release of hormones that regulate sexual maturation and reproduction. To test this hypothesis, immature sea lampreys will be exposed to natural and synthetic pheromones. Their brains will be examined to determine the neural pathways activated by the pheromone and the subsequent changes in reproductive hormone production using a combination of neurobiological and molecular biological approaches. It is likely that the data collected from this study will elucidate the mechanistic processes whereby pheromone signals are transmitted in the central nervous system and will document the extent of changes in hormone production and release in response to pheromone stimulation. Anticipated results from this project may have significant implications for the management of the sea lamprey, an invasive pest species in the Great Lakes. Graduate and undergraduate students will be offered unique training opportunities during these studies and a graduate student and possible interns from the Umatilla tribe will also be involved in these research activities.
