The Isolated Hypogastric Nerve‐vas Deferens Preparation of the Rat

1 Cholinoceptor agonists (arecoline --carbachol> acetylcholine> pilocarpine) potentiated contractions to field stimulation of rat vas deferens via the activation of an atropine-sensitive muscarinic receptor.2 The potentiating effect of carbachol was dependent on the level of calcium in the medium, being more potent at higher calcium concentrations. 3 The potentiating effect of carbachol was more pronounced in the epididymal than in the prostatic segment but was not attenuated by prazosin, an oc,-adrenoceptor antagonist. 4 Carbachol did not significantly modify the direct contractile effects of noradrenaline nor alter the field-stimulation-evoked release of noradrenaline from the epididymal vas deferens. 5 It is concluded that the potentiating effect of cholinoceptor agonists on the contractions to field stimulation in the rat vas deferens was not a result ofan enhancement of adrenergic neurotransmission.

Section: Discussionmentioning

confidence: 96%

“…It is well documented that acetylcholine can enhance the contractile response to nerve stimulation in both guinea-pig (Sjostrand, 1973) and rat (Graham et al, 1968;Liao & Freer, 1983) vas deferens. The molecular mechanism underlying this action, however, remains elusive.…”

Section: Introductionmentioning

confidence: 99%

Potentiation by cholinoceptor agonists of contractions to field stimulation of rat vas deferens

Lee

1985

“…In the present paper experiments will be described in which similar preparations from guinea-pigs and rats were used to study muscarinic and other non-nicotinic responses in the perfused hypogastric ganglion. For comparison other experiments were also done with fully isolated hypogastric nerve-vas deferens preparations (Hukovic, 1961;Graham, al Katib & Spriggs, 1968). A preliminary report of some of these findings has been published (Bentley, 1968).…”

Section: Introductionmentioning

confidence: 99%

Pharmacological studies on the hypogastric ganglion of the rat and guinea‐pig

Bentley

1972

Summary1. Preparations were developed whereby the hypogastric ganglion of the rat or guinea-pig was perfused through its vasculature with saline solutions. Drugs were injected into the perfusion stream, and their effects were indicated by contractions of the vas deferens. The base of this organ could be ligated to prevent the drugs reaching the smooth muscle via the blood vessels. For comparison, experiments were also performed on fully isolated preparations of the rat and guinea-pig hypogastric nerve-vas deferens, where the vas deferens was held in an inner bath, so that drugs added to the outer bath could act only on the ganglion. Attempts were made to demonstrate non-nicotinic receptors in these preparations.2. It was shown that the perfused hypogastric ganglion of the guinea-pig would respond repeatedly to several nicotinic stimulants, though autodesensitization eventually occurred. The fully isolated preparation behaved similarly, but desensitized much more rapidly. In contrast, the rat ganglion, either perfused or fully isolated, was remarkably insensitive to nicotinic stimulant drugs. 3. Neither species responded well to non-nicotinic stimulants; that from the guinea-pig gave small contractions to methacholine in about 33% of cases, but did not respond to (4-m-chlorophenyl-carbamoyloxy)-2-butynyl trimethylammonium chloride . With the rat, the situation was opposite. 4. The guinea-pig ganglion did not become more sensitive to non-nicotinic slUlants after some treatments known to sensitize the cat superior cervical ganglion. These include preganglionic tetanization, chronic decentralization, and removal of all potassium. Sensitization did occur, however, in the presence of physostigmine, after tachyphylaxis to dimethyl phenyl piperazinium iodide (DMPP) had developed, and when the preparation was perfused with a suspension of washed erythrocytes. 5. It is concluded that the responses of sympathetic ganglia vary from one species to another, and according to whether the organs are perfused or fully isolated.

“…The hypogastric nerve of the rat contains many ganglion cells situated close to the serous coat of the vas deferens; most of the fibres of the nerve are therefore preganglionic (Graham, Al Katib & Spriggs, 1968). From the ganglion cells short postganglionic nerves reach the vas deferens and travel in the serous coat to send fibres down into the muscle layers.…”

Section: Introductionmentioning

confidence: 99%

A comparison of the sensitivities of innervated and denervated rat vasa deferentia to agonist drugs

Birmingham¹,

Paterson²,

Wójcicki³

1970

Summary1. One vas deferens of a rat was denervated by stripping away the serous coat; the other vas was left intact as a control. One week later the sensitivity in vitro of both vasa deferentia to noradrenaline, adrenaline, dopamine, oxymetazoline or acetylcholine was measured. 2. Log concentration response curves for the mean responses of both vasa from a group of four rats for each drug were plotted. Denervated vasa were more sensitive than control vasa to noradrenaline (16-fold), to adrenaline (8-fold), to dopamine (2-fold) and to oxymetazoline (2-fold). Denervated vasa were more sensitive to acetylcholine over the lower half of the concentration range only. 3. It is concluded that these results support the theory that at least part of the increased sensitivity of denervated smooth muscle to catecholamines is due to an abolition or reduction of the neuronal uptake process. There is also a small non-specific increase in sensitivity. IntroductionThe hypogastric nerve of the rat contains many ganglion cells situated close to the serous coat of the vas deferens; most of the fibres of the nerve are therefore preganglionic (Graham, Al Katib & Spriggs, 1968). From the ganglion cells short postganglionic nerves reach the vas deferens and travel in the serous coat to send fibres down into the muscle layers. Cutting the hypogastric nerve trunk does not denervate the vas deferens (Sjostrand, 1965), but stripping away the serous coat interrupts the short postganglionic fibres which then degenerate to leave denervated smooth muscle which is supersensitive to noradrenaline (Birmingham, 1970). We have now compared the sensitivity of innervated and denervated rat vasa deferentia to several agonist drugs to determine the degree to which this supersensitivity is specific for noradrenaline.