Preganglionic and Postganglionic Stimulation of the Guinea‐pig Isolated Vas Deferens Preparation

A comprehensive investigation of the innervation of the vas deferens of the mouse was made using pharmacological, histochemical and electronmicroscopical techniques. Guanethidine inhibited the response of the vas to transmural stimulation and potentiated the response to noradrenaline (NA). Phentolamine abolished responses to NA and to transmural stimulation. After chemical sympathectomy degenerative changes were seen in presumptive noradrenergic axons; histochemical fluorescence due to catecholamines was absent. The vas failed to respond to transmural stimulation, and a 10‐fold increase in sensitivity of the vas to exogenous NA was observed. NA is shown to diffuse slowly through this tissue whose muscle cells are densely packed. This is discussed in relation to the apparent ‘insensitivity’ of the vas to exogenous NA. A cholinergic component was identified histochemically which did not contribute significantly to the motor response of the vas as chemical sympathectomy abolished completely the motor response elicited by transmural stimulation. It is concluded that NA is the motor transmitter for the smooth muscle of the vas deferens of the mouse.

Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Noradrenaline and Motor Transmission in the Vas Deferens of the Mouse

Jones

Spriggs

1975

“…Field stimulation (Birmingham & Wilson, 1963) of the vas, suspended between two parallel platinum wire electrodes immersed in a 50 ml bath, was by means of an SRI 6053 stimulator delivering rectangular pulses of 0.3 ms duration at frequencies of 30 Hz and of supramaximal voltage every 3.25 minutes. An oscilloscope was used to confirm the uniformity and reproducibility of the stimulation parameters under experimental conditions with the electrodes totally immersed in the bathing fluid.…”

Section: Methodsmentioning

confidence: 99%

“…Previous pharmacological studies of the vas deferens have been confined largely to organs obtained from guinea-pigs or rats and the innervation of these structures is considered to be adrenergic in nature (Hukovic, 1961;Birmingham & Wilson, 1963;Graham, Al Katib & Spriggs, 1968;Swedin, 1971;Furness, 1974). The existence of a physiologically important cholinergic component in the innervation was largely accounted for by the discovery of ganglionic relays in what had hitherto been considered as classical post-ganglionic sympathetic nerves (Sjostrand, 1962;Graham et al, 1968).…”

Section: Introductionmentioning

confidence: 99%

An Inhibitory Effect of Atropine on Responses of the Vas Deferens of the Mouse to Field Stimulation

Jones

Spriggs

1975

1 Atropine is shown to impair responses of the vas deferens of the mouse to field stimulation by acting at a site proximal to the smooth muscle cells. 2 The inhibitory effect of atropine is prevented by desmethylimipramine and reversed by dexamphetamine, and appears similar to the adrenergic-neurone blockade of guanethidine. 3 Electronmicroscopical studies show the presence in vas of presumptive noradrenergic axons which have acetylcholinesterase reaction product associated with their axolemmae. 4 These results are discussed in relation to the controversial hypothesis of a 'cholinergic link' in noradrenergic transmission.

“…The sympathetic nerves supplying the vas deferens are uncharacteristic inasmuch as they relay at peripheral synapses (Birmingham & Wilson, 1963;Kuriyama, 1963;Falck, Owman & Sjostrand, 1965;Ferry, 1967). Birmingham & Wilson (1963) devised a simple method of transmural stimulation for triggering this rich intramural network of short postganglionic noradrenergic nerve fibres, thereby contracting the vas, since which time the pharmacology of this preparation has been extensively studied.…”

Section: Introductionmentioning

confidence: 99%

Potentiation by Substance P of Contractions of the Isolated Vas Deferens of the Mouse Elicited by Electric Field Stimulation and by Drugs

Blackwell¹,

James²,

Starr³

1978

1 Isolated vasa deferentia from the mouse were opened longitudinally and suspended in Krebs solution at 37°C in an organ bath. Contractions of the muscle were elicited by electric field stimulation, noradrenaline (10-6 M) and acetylcholine (10-6 M). Continued transmural stimulation evoked a biphasic response comprising a rapid twitch followed about 10s later by a smaller, sustained rise in muscle tone. 2 The amplitudes of nerve-mediated and drug-induced responses were considerably potentiated by substance P-(SP) in the dose range 10-12 to 10-M. Higher concentrations of SP were directly spasmogenic. The sensitizing property of SP was dose-dependent and was usually well maintained, but always disappeared quickly on washing the preparation. In some experiments SP facilitated the twitch, but not the subsequent phase of the electrically-induced contraction or the response to externally applied noradrenaline. 3 Phentolamine (10-6 M) failed to block this effect of SP, but itself potentiated the nerve-mediated twitch, and completely abolished the sustained secondary contraction. 4 Desmethylimipramine (10-6 M) enhanced the delayed contraction but not the immediate contraction. 5 The uptake of tritiated noradrenaline (3 x lo-M) by vasa was inhibited by desmethylimipramine (10-6M) and increased by nialamide (3 x 10-5M), but was not modified by SP (10-6M). 6 Nerve-mediated release of accumulated radioactivity was accelerated by phentolamine, but not by SP or desmethylimipramine. 7 These findings suggest that SP sensitizes the muscle cells to depolarizing stimuli but that it has no facilitatory effect on sympathetic neural elements.