title: Octopamine and tyramine regulate the activity of reproductive visceral muscles in the adult female blood-feeding bug,Rhodnius prolixus.
abstract: The role of octopamine and tyramine in regulating spontaneous contractions of reproductive tissues was examined in the femaleRhodnius prolixusOctopamine decreased the amplitude of spontaneous contractions of the oviducts and reduced RhoprFIRFa-induced contractions in a dose-dependent manner, whereas tyramine only reduced the RhoprFIRFa-induced contractions. Both octopamine and tyramine decreased the frequency of spontaneous bursal contractions and completely abolished the contractions at 5×10-7mol l-1and above. Phentolamine, an octopamine receptor antagonist, attenuated the inhibition induced by octopamine on the oviducts and the bursa. Octopamine also increased the levels of cAMP in the oviducts, and this effect was blocked by 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. The tyramine receptor antagonist yohimbine failed to block the inhibition of contractions induced by tyramine on the bursa, suggesting that tyramine may be acting on the Octβ receptor in the bursa.
authors.affiliation: University of Toronto Mississauga, Department of Biology, Mississauga, ON, Canada L5L1C6 sam.hana@mail.utoronto.ca.
authors.forename: Sam
authors.identifier: 0000-0002-0847-7159
authors.initials: S
authors.lastname: Hana
authors.affiliation: University of Toronto Mississauga, Department of Biology, Mississauga, ON, Canada L5L1C6.
authors.forename: Angela B
authors.initials: AB
authors.lastname: Lange
mesh_terms: D000818:Animals; D000242:Cyclic AMP / Q000032:analysis; D005260:Female; D009119:Muscle Contraction / Q000187:drug effects*; D009130:Muscle, Smooth / Q000187:drug effects; D009655:Octopamine / Q000494:pharmacology*; D010057:Oviducts / Q000187:drug effects*; D010646:Phentolamine / Q000494:pharmacology; D017982:Receptors, Biogenic Amine; D012239:Rhodnius / Q000187:drug effects*; D014439:Tyramine / Q000494:pharmacology*; D015016:Yohimbine / Q000494:pharmacology
chemical_list: D017982:Receptors, Biogenic Amine; C027604:norsynephrine receptor; C066175:tyramine receptor; D009655:Octopamine; D015016:Yohimbine; D000242:Cyclic AMP; D014439:Tyramine; D010646:Phentolamine
keywords: Bursa; Contractions; Cyclic AMP; Inhibition; Oviducts