@entity1238 embryos at the blastula-early tail bud stage were exposed to @entity1063 or @entity11879 dissolved in culture saline until they reached the larval stage. The left-right asymmetry of the heart and gut was then examined. We found that these adrenergic neurotransmitters induced situs inversus in the heart and/or gut in up to 35% of tested neurula embryos. @entity1063 -induced situs inversus was blocked by the alpha-1 adrenergic antagonist @entity3159 . Furthermore, @entity3365 , a @entity460 ionophore, also increased the incidence of situs inversus up to 54% when late-neurula embryos were exposed to the solution. @entity3365 treatment initiated before neural groove formation was less effective. The incidence of situs inversus induced by these reagents decreased towards the control level (2.2%, 25 untreated embryos out of 1127 embryos in total) in embryos past the stage of neural tube closure. In the present experiments we obtained 22 gut-only situs inversus embryos having an inverted gut and a normal heart. In contrast, such embryos were not observed among the 1127 untreated embryos. An adrenergic signal mediated by an increase in intracellular free @entity460 may be involved in the asymmetrical visceral morphogenesis of @entity1238 embryos.

Adrenergic neurotransmitters and @entity460 ionophore-induced situs inversus viscerum in XXXX embryos.

@entity1238 :: ('8355', 'Species') :: ['Xenopus laevis', 'Xenopus'] @entity11879 :: ('MESH:D009655', 'Chemical') :: ['octopamine'] @entity460 :: ('MESH:D002118', 'Chemical') :: ['calcium'] @entity3365 :: ('MESH:D000001', 'Chemical') :: ['A23187'] @entity3159 :: ('MESH:D011224', 'Chemical') :: ['prazosin'] @entity1063 :: ('MESH:D009638', 'Chemical') :: ['Norepinephrine', 'norepinephrine']
@entity1238 :: (8355,Species) :: ['Xenopus laevis']
