ABSTRACTPHEROMONE MODULATION OF LOCOMOTOR RHYTHMICITY IN ADULT FEMALE SEA LAMPREYByErin J. Walaszczyk All animals are partially controlled by a number of circadian rhythms. These are physical, behavioral, or genetic changes that occur on an approximate 24 hour time cycle and allow the organism to coordinate its internal and external environments. These rhythms are endogenous, but can be affected by external, environmental cues. Sea lamprey offer a unique model to understand locomotor rhythmicity, as throughout their life cycle they switch from a nocturnal rhythm in locomotor activity to arrhythmic multiple times. Adult female sea lamprey respond behaviorally to mature male sex pheromones that guide them to appropriate spawning grounds and induces spawning behaviors. In this dissertation, the overall hypothesis that locomotor rhythmicity in adult female sea lamprey is modulated by sex pheromone compounds is tested. In Chapter 1, field tests confirm that pre-ovulated and ovulated female locomotor activity is affected during exposure to spermiated male washings (SMW), and that in ovulated females SMW can alter the locomotor pattern. In Chapter 2, effects of individual SMW compounds are investigated using controlled laboratory studies, and results show that SMW as well as two components of SMW, 3-keto petromyzonol sulphate (3kPZS) and petromyzonal sulfate (PZS), have differential effects on pre-ovulated and ovulated female locomotor activity. Chapter 3 demonstrates that there are effects of these sex pheromones on the GABAergic system in the brain and pineal complex related to neural circuits that guide locomotor activity production. Chapter 4 investigates the endogenous circadian system, providing evidence that sex pheromone compounds alter the molecular framework responsible for circadian rhythms in the proposed master circadian clock, the pineal gland, as well as peripheral clocks in the brain. Studies here provide a rare example of an exogenous stimuli on circadian locomotor production and add to the knowledge of sex pheromone influences on behavior, circadian timekeeping mechanisms, and locomotor activity and rhythm production in this species.
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