title: Biochemical and functional properties of large and small dense-core vesicles in sympathetic nerves of rat and ox vas deferens.
abstract: A comparative study of the noradrenaline storing vesicles in vas deferens from ox and rat was performed. Microsomal fractions were subjected to density gradient centrifugation. In rat, noradrenaline and dopamine beta-hydroxylase were mainly present in the upper fractions of the gradient, which is consistent with the predominance of light (small dense-core) vesicles in this species. In ox, noradrenaline, dopamine and dopamine beta-hydroxylase were found in the gradient in a bimodal distribution. This is consistent with the presence of about equal numbers of small and large dense-core vesicles in this species. On the other hand, chromogranin A, immunologically related proteins and enkephalin-like immunoreactivity were only present in the dense (large dense-core) vesicle population. In order to study the capability of light and dense vesicles to synthesize noradrenaline we "pulse-labelled" ox vasa deferentia with [3H]tyrosine. Already 3.5 min after the pulse both types of vesicles contained [3H]noradrenaline and [3H]dopamine. During longer "chase" periods the amount of [3H]dopamine gradually declined. We conclude that dense (large dense-core) vesicles contain chromogranin A, immunologically related proteins and enkephalin-like immunoreactivity whereas light (small dense-core) vesicles are devoid of these components. Both types of vesicles contain dopamine beta-hydroxylase and can synthesize noradrenaline from dopamine under in vivo conditions.
mesh_terms: D000818:Animals; D002395:Catecholamines / Q000032:analysis*; D002417:Cattle; D002458:Cell Fractionation / Q000379:methods; D004299:Dopamine beta-Hydroxylase / Q000032:analysis*; D004744:Enkephalin, Methionine / Q000032:analysis*; D066298:In Vitro Techniques; D008297:Male; D009638:Norepinephrine / Q000032:analysis; D051381:Rats; D013564:Sympathetic Nervous System / Q000378:metabolism / Q000648:ultrastructure*; D013572:Synaptic Vesicles / Q000032:analysis; D014649:Vas Deferens / Q000294:innervation* / Q000378:metabolism
chemical_list: D002395:Catecholamines; D004744:Enkephalin, Methionine; D004299:Dopamine beta-Hydroxylase; D009638:Norepinephrine