MSc Exit Seminar -Sam Hana -Wednesday, August 16, 2017

MSc Exit Seminar

Wednesday, August 16, 2017 at 10:10 am, CC-2150 – University of Toronto at Mississauga

Sam Hana (Lange Lab)

“The Role of Octopamine and Tyramine in the Adult Female Reproductive System of Rhodnius prolixus“

Abstract

Octopamine and tyramine are neuroactive chemicals involved in many physiological processes acting as neurotransmitters, neuromodulators and neurohormones. Octopamine and tyramine are crucial in modulating reproductive processes in insects. In Rhodnius prolixus, octopamine decreased the amplitude of muscle contractions and reduced the RhoprFIRFa-induced contraction of the oviducts in a dose-dependent manner, whereas tyramine only reduced the RhoprFIRFa-induced contractions. At the bursa, octopamine and tyramine reduced the frequency and abolished contractions at higher concentrations. Octopamine also increased the levels of cAMP in the oviducts, and this effect was blocked by an alpha-adrenergic blocker, phentolamine. Dibutyryl cyclic AMP mimicked the effects of octopamine by reducing the frequency of bursal contractions, suggesting that the octopamine receptor may act by an Octβ receptor. These events are mediated by G protein coupled receptors (GPCRs). The cDNA sequences of two receptors, RhoprOctβ2-R and RhoprTyr1-R, has been cloned and characterized; the receptor transcripts are expressed in all female reproductive tissues. Injection of octopamine and tyramine into mated and fed adult females resulted in a higher number of eggs produced. Overall, octopamine and tyramine modulate the female reproductive tissues leading to successful ovulation, fertilization and the oviposition of eggs.