Ca2+ handling properties of microsomal subfractions of rat vas deferens smooth muscle

The rat vas deferens smooth muscle microsomes on isopycnic centrifugation gave two fractions, namely F2 (15–30% sucrose) and F3 (30–40% sucrose), with comparable ATP-dependent azide-insensitive Ca2+-uptake capacities, although these fractions differed from each other in various enzyme marker activities. The fractions F2 and F3 also show similar pH profiles for the ATP-independent and ATP-dependent Ca2+ uptake, and similar ionized Ca2+-concentration dependence for the ATP-dependent Ca2+ uptake. However, the fractions F2 and F3 differ from each other in that: (a) F3 shows higher permeability to Ca2+, and (b) F3 shows higher stimulation of the ATP-dependent Ca2+ uptake by oxalate. The F3 fraction can also be used to obtain membrane vesicles loaded with Ca2+ oxalate in the presence of ATP. However, the yield of the Ca2+ oxalate enriched fraction is too low to permit their further characterization.

Download Full-text

Simultaneous measurement of contractile effects in the circular and longitudinal smooth muscle of the rat vas deferens by drugs perfused externally or via the lumen

British Journal of Pharmacology ◽

10.1111/j.1476-5381.1985.tb11071.x ◽

1985 ◽

Vol 85 (4) ◽

pp. 737-746 ◽

Cited By ~ 4

Author(s):

Pedro A. Busatto ◽

Aron Jurkiewicz

Keyword(s):

Smooth Muscle ◽

Simultaneous Measurement ◽

Vas Deferens ◽

Rat Vas Deferens ◽

Longitudinal Smooth Muscle

Download Full-text

Effect of NO donors on protein phosphorylation in intact vascular and nonvascular smooth muscles

AJP Heart and Circulatory Physiology ◽

10.1152/ajpheart.2001.280.4.h1565 ◽

2001 ◽

Vol 280 (4) ◽

pp. H1565-H1580 ◽

Cited By ~ 8

Author(s):

James K. Hennan ◽

Jack Diamond

Keyword(s):

Smooth Muscle ◽

Protein Kinase ◽

Protein Phosphorylation ◽

Vas Deferens ◽

Smooth Muscles ◽

Rat Aorta ◽

Rat Vas Deferens ◽

Two Dimensional Gel Electrophoresis ◽

Relaxant Response ◽

Underlying Mechanisms

It is generally well accepted that nitrovasodilator-induced relaxation of vascular smooth muscle involves elevation of cGMP and activation of a specific cGMP-dependent protein kinase [protein kinase G (PKG)]. However, the protein targets of PKG and the underlying mechanisms by which this kinase leads to a relaxant response have not been elucidated. Several types of smooth muscle, including rat myometrium and vas deferens, are not relaxed by sodium nitroprusside, even at concentrations that produce marked elevation of cGMP and activation of PKG. The main objective of our studies was to compare PKG-mediated protein phosphorylation in intact rat aorta, rat myometrium, and rat vas deferens using two-dimensional gel electrophoresis. In intact rat aorta, seven PKG substrates were detected during relaxation of the tissue. None of the PKG substrates identified in the rat aorta appeared to be phosphorylated in the myometrium or vas deferens after administration of various cGMP-elevating agents. Thus the failure of the rat myometrium and rat vas deferens to relax in the face of cGMP elevation and PKG activation may be due to a lack of PKG substrate phosphorylation.

Download Full-text

Reorganization of the innervation of the vas deferens after sympathetic decentralization

AJP Regulatory Integrative and Comparative Physiology ◽

10.1152/ajpregu.1996.271.6.r1481 ◽

1996 ◽

Vol 271 (6) ◽

pp. R1481-R1488

Author(s):

K. Kihara ◽

H. Kakizaki ◽

W. C. de Groat

Keyword(s):

Electrical Stimulation ◽

Vas Deferens ◽

Ganglion Cells ◽

Rat Vas Deferens ◽

Pelvic Nerve ◽

Hypogastric Nerve ◽

Normal Side ◽

Efferent Pathways ◽

Stimulation Of

Reorganization of autonomic efferent pathways to the rat vas deferens was noted after chronic (30 days) sympathetic decentralization produced by hypogastric nerve (HGN) transection. In normal rats, electrical stimulation of the HGN elicited an increase in vasal pressure (VP) bilaterally, whereas pelvic nerve (PN) stimulation did not alter VP. However, after unilateral HGN transection, stimulation of the PN on the transected side but not on the normal side increased VP. The decentralized vas exhibited larger VP responses to stimulation of the contralateral HGN in comparison with the normal vas. After bilateral HGN transection, PN-induced VP responses were elicited at lower stimulus intensities than in rats with unilateral transections. PN-induced VP responses were blocked by hexamethonium and prazosin but were not altered by atropine. Distension of the vas lumen occurred after decentralization. PN-induced VP responses were not detectable in extremely distended vas. These data indicate that, after degeneration of sympathetic preganglionic axons, decentralized adrenergic ganglion cells are reinnervated by parasympathetic or sympathetic preganglionic pathways and that the reinnervation influences vasal function.

Download Full-text