SEARCH · PubMed Health

Results for “Vas Deferens”

Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 37 records · Page 2Linked to original sources

PubMed1979

Quantitative age related histologic changes in the human vas deferens.

Sections of vas deferens from 50 men between 27 and 82 years of age were examined histologically for evidence of changes in muscle area and for changes in per cent of the cross-sectional area of the vas deferens that was occupied by muscle and connective tissue as a function of age. No variation in quantitative measurement of muscle or connective tissue could be correlated with age but a diffuse increase in unmeasurable amounts of connective tissue was seen with increasing age.

Adult↗

PubMed1993

Evans blue blocks P2X-purinoceptors in rat vas deferens.

In rat vas deferens, Evans blue 100 microM increased contractions elicited by high K+ and by noradrenaline but markedly reduced contractions elicited by the P2X-purinoceptor-selective agonist alpha,beta-methylene ATP (3 microM). The concentration-response curve of alpha,beta-methylene ATP was shifted to the right by Evans blue 30 microM and the maximal contraction was increased. In tissues incubated with nifedipine 10 microM, Evans blue 100 microM tended to increase the residual contraction elicited by noradrenaline and abolished the residual response to alpha, beta-methylene ATP (3 microM). The concentration-response curve of alpha,beta-methylene ATP was progressively shifted to the right by increasing concentrations of Evans blue in the presence of nifedipine; maximal contractions were increased by Evans blue 10 and 30 but not 100 microM. From the shifts to the right caused by Evans blue 30 microM, apparent pKB values of 5.9 (no nifedipine) and 6.0 (nifedipine present) were calculated. It is concluded that Evans blue blocks P2X-purinoceptors in rat vas deferens and in addition causes a non-receptor-specific enhancement of contractions.

Adenosine Triphosphate↗

PubMed1993

Role of intracellular Ca2+ stores in smooth muscle contractions of the guinea pig vas deferens.

Guinea pig vas deferens was used as an animal model for alpha-1 adrenoceptor (alpha 1-receptor) mediated contractions in human hyperplastic prostatic tissue. The selective alpha 1-receptor agonist, phenylephrine (PE), induced fully reversible, dose-dependent contractions antagonized by increasing concentrations of the alpha 1-receptor blockers prazosin (1-100 nM) and YM 617 (0.1-10 nM). Removal of extracellular Ca2+ reduced PE-evoked contractions in a time-dependent manner. Nifedipine (1-1000 nM), a blocker of voltage-dependent L-type Ca2+ channels (VDCC), inhibited the PE-induced response by up to 65%. Removal of extracellular Ca2+ abolished the alpha 1-agonist reactivity in a time-dependent fashion. To elucidate the participation of intracellular Ca2+ stores in alpha 1-receptor-mediated contractions, the tissue was pretreated with ryanodine (10 microM) or thapsigargin (0.1 microM), established inhibitors of Ca2+ release from intracellular pools. Both substances reduced the PE contractions by up to 80%. Nifedipine suppressed the remaining contractions completely. This provides evidence that Ca2+ influx through VDCC and Ca2+ release from intracellular stores contribute to alpha 1-receptor-mediated contractions in the guinea pig vas deferens and may be important in obstructive benign prostatic hyperplasia.

Adrenergic alpha-Antagonists↗

PubMed1999

Ultrastructural changes in the vas deferens of langur monkeys Presbytis entellus entellus after vas occlusion with styrene maleic anhydride and after its reversal.

Ultrastructural changes in the vas deferens of langur monkeys after 150 days of vas occlusion with styrene maleic anhydride (SMA) and after 150 days of noninvasive reversal are reported. The vas deferens of the sham-operated control animals revealed active secretory and absorptive functions. The basal cells showed prominent nucleus and sparse cytoplasmic organelles, and the principal cells characterized by oval or irregular nucleus, well developed mitochondria, Golgi bodies, rough endoplasmic reticulum, secretory granules in the Golgi area, free ribosomes, and glycogen granules in the supranuclear region suggesting secretory function. Vesicles and stereocilia in the apex region suggested absorptive functions of the vas deferens. Vas occlusion by SMA resulted in exfoliation of epithelial cells, pyknotic nuclei, and vacuolated cytoplasm virtually devoid of cytoplasmic organelles and stereocilia. After noninvasive reversal, the vas epithelium regained a state of normalcy as evidenced by prominent plasma membrane, nucleus, cytoplasmic organelles, and stereocilia. The results suggest that the exfoliation of the epithelium due to vas occlusion by SMA regains normalcy after 150 days of noninvasive reversal.

Animals↗

PubMed2000

Down-regulation of Na(+)/K(+)-ATPase alpha(2) isoform in denervated rat vas deferens.

In the rat vas deferens, an organ richly innervated by peripheral sympathetic neurons, we have demonstrated recently the expression of alpha(1) and alpha(2), but not alpha(3) isoforms of the alpha subunit of Na(+)/K(+)-ATPase (EC 3.6.1.37), a membrane-bound enzyme of vital function for living cells (Noël et al., Biochem Pharmacol 55: 1531-1535, 1998). In the present work, we characterized, qualitatively and quantitatively, Na(+)/K(+)-ATPase alpha isoforms in denervated rat vasa deferentia. [(3)H]Ouabain binding at concentrations defined for high-affinity isoforms (alpha(2) and/or alpha(3)) detected only one class of specific binding sites in control (C) and denervated (D) vas deferens. Although the dissociation constant was similar for both groups [K(d) = 138 +/- 14 nM (C) and 125 +/- 8 nM (D)], a marked decrease in density was observed after denervation [716 +/- 81 fmol.mg protein(-1) (C) and 445 +/- 34 fmol.mg protein(-1) (D), P < 0.05]. In addition, western blotting revealed that denervated vasa deferentia produce the alpha(1) and alpha(2) isoforms but not alpha(3), just as we reported for the controls previously (Noël et al., Biochem Pharmacol 55: 1531-1535, 1998). Densitometric analysis showed a decrease of the alpha(2) isoform by about 40% in denervated organs, in very good agreement with what was shown with the [(3)H]ouabain binding technique, but no significant change in alpha(1) isoform density. Truncated alpha(1) (alpha(1)T), an isoform suggested to exist in the guinea pig vas deferens, was not detected. Altogether, our results demonstrated that Na(+)/K(+)-ATPase alpha(2) is down-regulated after sympathetic denervation of the rat vas deferens.

Animals↗

PubMed1990

The effect of inhibitors of prostaglandin formation on contraction of the rat, rabbit and human vas deferens.

1. The rat vas deferens releases both PGE2 and PGF2 alpha under basal conditions in vitro but the human vas deferens synthesizes prostaglandins only when arachidonic acid is supplied exogenously. 2. The release of PGE2 and PGF2 alpha is augmented by alpha-adrenoceptor activation or by BaCl2, both of which cause contraction. 3. Release of PGE2 and PGF2 alpha is substantially inhibited by indomethacin 10 micrograms ml-1 which does not affect contraction. 4. Contraction is strongly inhibited by higher concentrations of indomethacin (50-80 micrograms ml-1). 5. It is concluded that the release of PGE2 and PGF2 alpha from the rat and human vas deferens is not correlated with contraction.

Animals↗

PubMed1981

The vulnerability of the vas deferens.

Transection of the vas deferens is considered a disaster, but other manipulations may have unpredictable and hitherto undocumented effects. In order to delineate the structural changes in the vas deferens after operative manipulation, 40 Wistar rats (300-500 g) were divided into four groups and subjected to four different operative manipulations (grasping with fingers, nontoothed Adson forceps, bulldog vascular clamp, clamping with "mosquito" hemostat). Histologic studies performed at 6 wk postmanipulation demonstrated a variable intra- and transmural inflammatory reaction in all groups. Thirty percent of the specimens grasped by the forceps showed disruption of the muscle wall. One-hundred percent of the specimens clamped by the hemostat showed mural disruption and marked inflammatory reaction; in addition 30% had an associated abscess. Therefore all manipulation of the vas deferens should be minimized to avoid triggering inflammation and secondary obstruction. Grasping with a nontoothed forceps results in appreciable damage. Clamping with a hemostat is as serious as complete transection.

Animals↗

PubMed1990

Evidence that dopamine is acting at alpha-adrenoceptors of the rat vas deferens.

In the rat vas deferens, a vast number of experiments have shown that the alpha-adrenoceptors present are of two types: alpha 1 and alpha 2. This series of experiments with the isolated rat vas deferens was designed to probe by pharmacological means, the nature of the responses elicited by neurogenic transmural stimulation and also those responses evoked by exogenous NE and DA. The methodology required the production of chemical denervation, neurotransmitter depletion, and the use of specific adrenoceptor blockers. The results obtained with the blocking agents, yohimbine or prazosin versus NE and DA, were pA2 values that were virtually interchangeable. The effects of chemical alteration with 6-OH-DA or reserpine point to a certain similarity and interdependence of the mechanism of action for the two neurotransmitters. Therefore, it is suggested that these two transmitters act at the same receptor site or share a common receptive microenvironment in the rat vas deferens.

Animals↗

PubMed1996

Differential distribution of adenosine A2 receptors in the epididymal and prostatic portions of the rat vas deferens.

In the rat vas deferens there are prejunctional A1 receptors mediating inhibition of transmitter release and post-junctional A1 and A2 receptors mediating enhancement and inhibition of contractions respectively. In this study the distribution of adenosine receptors in the prostatic and epididymal portions of the bisected rat vas deferens was investigated. The pre- and post-junctional A1 receptors were present on both portions of the bisected tissue. However, post-junctional A2 receptors appear to be present only in the prostatic region, showing that adenosine receptors are differentially distributed along the length of the rat vas deferens.

Adenosine↗

PubMed1994

Maxi K+ channels on human vas deferens epithelial cells.

The vas deferens forms part of the male reproductive tract and extends from the cauda epididymis to the prostate. Using the patch clamp technique, we have identified a Ca(2+)-activated, voltage-dependent, maxi K+ channel on the apical membrane of epithelial cells cultured from human fetal vas deferens. The channel had a conductance of approximately 250 pS in symmetrical 140 mM K+ solutions, and was highly selective for K+ over Na+. Channel activity was increased by depolarization and by an elevation of bath (cytoplasmic) Ca2+ concentration, and reduced by cytoplasmic Ba2+ (5 mM) but not by cytoplasmic TEA (10 mM). Channel activity was also dependent on the cation bathing the cytoplasmic face of the membrane, being higher in a Na(+)-rich compared to a K(+)-rich solution. We estimated that up to 600 maxi K+ channels were present on the apical membrane of a vas cell, and that their density was 1-2 per mu 2 of membrane. Activity of the channel was low on intact cells, suggesting that it does not contribute to a resting K+ conductance. However, fluid in the lumen of the human vas deferens has a high K+ concentration and we speculate that the maxi K+ channel could play a role in transepithelial K+ secretion.

Calcium↗

PubMed1992

Testosterone stimulates prostanoid production by rat vas deferens.

The rat isolated vas deferens produces and releases prostanoids into an incubation medium. Production of these substances from the exogenous precursor 14C arachidonic acid was studied in prepubertal, pubertal and adult animals. Synthesis of prostaglandin F, prostaglandin E, prostaglandin D and thromboxane B2 is lower in prepubertals arid increases significantly in pubertals, with no further modifications in adults. Castration of pubertals and adults dramatically reduces the production of all measured arachidonic acid metabolites but does not modify it in prepubertals. Replacement therapy with testosterone propionate significantly enhances prostanoid production in pubertal and adult castrated rats. Similar treatment on normal prepubertals also increases synthesis, indicating that androgens could be modulators of prostanoid synthesis in vas deferens. The lower effects obtained treating castrated adults with progesterone and with 17-beta estradiol suggest an action, at least partially specific for androgenic steroids. It is concluded that prostanoid production by the rat vas deferens from an exogenous precursor is closely related to the presence of androgens.

Age Factors↗

PubMed1977

Some properties of the smooth muscle of mouse vas deferens.

1. Contractions of the mouse vas deferens in response to electrical stimulation differ form those recorded form the guinea-pig vas deferens in that they are abolished by tetrodotoxin. 2. Changes in membrane potentials were recorded form the smooth muscle of both preparations in response to stimulation with current pulses applied by an intracellular electrode and by alrge extracellular plate electrodes. 3. Both preparations behaved similarly in response to intracellular stimulation. Electrotonic potentials in response to extracellular current pulses spread in a longitudinal direction in the guinea-pig vas deferens in accordance with the cable-like properties of this preparation. In contrast, no longitudinal spread of eletrotonus was observed in the mouse vas deferens. 4. Responses to nerve stimulation differed in the two preparations. In the guinea-pig, single stimuli caused excitatory junction potentials (e.j.p.s) which gave rise to action potentials. Some cells from the mouse vas deferens showed similar e.j.p.s and action potentials, although the threshold for the initiation of action potentials was lower and more variable. 5. The majority of cells in the mouse vas deferens failed to show action potentials in response to a single stimuli even though the amplitude of e.j.p.s was from 35 to 40 mV. This was probably due to the large resting membrane potentials of these cells, as all-or-nothing action potentials could be evoked if successive e.j.p.s were allowed to sum with each other or if a depolarizing current pulse was applied at the peak of an e.j.p. 6. The nature of the response to nerve stimulation recorded from differnt cells in the mouse vas deferens could be correlated with the amplitude and time course of the response of the same cell to intracellular stimulation. 7. It is concluded that individual smooth muscle cells in both preparations are probably coupled electrically but that there are few, if any, low resistance pathways in the longitudinal direction in the mouse vas deferens.

Action Potentials↗

PubMed2006

The bioassay of cannabinoids using the mouse isolated vas deferens.

The mouse isolated vas deferens is a nerve-smooth muscle preparation that serves as a highly sensitive and quantitative functional in vitro bioassay for cannabinoid CB1 receptor agonists. Additionally, it is commonly used as a bioassay for competitive surmountable CB1 receptor antagonists, and also provides a means for distinguishing neutral CB1 antagonists from CB1 inverse agonists. The bioassay of CB1 receptor agonists relies on the ability of these ligands to produce concentration-related decreases in the amplitude of electrically evoked contractions of the vas deferens. This they do by acting on naturally expressed prejunctional neuronal CB1 receptors to inhibit release of the contractile neurotransmitters, noradrenaline and ATP, that is provoked by the electrical stimulation. The bioassay of competitive surmountable CB1 receptor antagonists involves determining the ability of these compounds to produce parallel dextral shifts in CB1 receptor agonist log concentration-response curves in electrically stimulated tissues. The mouse vas deferens has also been used to measure the ability of anandamide to activate vanilloid (TRPV1) receptors, to monitor modulation by cannabinoids such as 6"-azido-2"-yne-cannabidiol and abnormal cannabidiol of contractions elicited in electrically unstimulated tissues by agonists for P2X purinoceptors or alpha1-adrenoceptors, and as a bioassay for the nonpsychoactive plant cannabinoid cannabidiol.

Animals↗

PubMed1981

Role of alpha-adrenergic receptors in denervation supersensitivity of rat vas deferens.

Contractile responses of rat vas deferens were studied with particular attention directed to the role of receptors and neuronal control. Marked contraction of the vas deferens was observed with alpha-adrenergic agonists, depending on their concentrations. This tissue had a low sensitivity to ACh. Four days after denervation, this tissue showed a supersensitivity to alpha-adrenergic agonists and a high K+ concentration, but not to ACh. The increase in sensitivity to alpha-agonists resulted in an enhancement of the maximal response and a shift of the concentration response curve to lower concentrations of these reagents. Alterations were seen in the alpha-adrenergic receptors in the rat vas deferens, assayed by measuring the binding of [3H]WB4101. The maximal binding sites decreased significantly to 86 from 142 fmoles per mg protein. The affinity of the receptors for alpha-agonist, determined by measuring the ability of agonists to displace bound [3H] WB4101, increased significantly, while the affinity to alpha-antagonists remained unchanged. Studies on [3H]QNB binding indicated no significant change in muscarinic ACh receptors after denervation. Thus, supersensitivity of the alpha-adrenergic mechanism mediated by a specific change in affinity of alpha-receptors occurs after denervation of rat vas deferens. These changes in sensitivity and in receptors are discussed in relation to the characteristics and roles of alpha-receptors in the rat vas deferens.

Acetylcholine↗

PubMed1989

Examination of the paradoxical lack of responsiveness of the guinea-pig vas deferens to tyramine.

1. The isolated superfused vas deferens from the guinea-pig was more sensitive to the contractile action of noradrenaline than that from the rat. Tyramine had about 10% of the potency of noradrenaline on the rat vas deferens, but had no contractile activity on the guinea-pig vas deferens (potency less than 0.1% of noradrenaline). 2. The response of the guinea-pig vas deferens to noradrenaline was not affected by tyramine in a concentration that produced a clear contractile response of the rat vas deferens. 3. Noradrenaline and tyramine released less radioactivity from guinea-pig than from rat vasa deferentia in which noradrenergic transmitter stores had been labelled with 3H-noradrenaline. In vasa deferentia from either species, tyramine released less radioactivity than noradrenaline. 4. Pretreatment with the monoamine oxidase inhibitor iproniazid increased the amount of radioactivity released by tyramine from vasa deferentia of both species, increased the contractile response of the rat vas deferens to tyramine, and resulted in the appearance of a contractile response to tyramine in the guinea-pig vas deferens. 5. alpha-methyltyramine, which is not a substrate for monoamine oxidase, had about the same potency as tyramine in releasing radioactivity from vasa deferentia of both species, and in contracting the rat vas deferens, but was virtually without contractile activity on the guinea-pig vas deferens. 6. Pretreatment with iproniazid resulted in the appearance of a contractile response to alpha-methyltyramine in the guinea-pig vas deferens. 7. Pretreatment with iproniazid resulted in change in the composition of the radioactivity released by tyramine, with an increase in the proportion of noradrenaline and a decrease in the proportion of deaminated products. There was also an increase in the amount of endogenous noradrenaline released by tyramine. 8. It was concluded that the main factor accounting for the lack of reactivity of the guinea-pig vas deferens to tyramine is intraneuronal metabolism of the noradrenaline displaced by it.

Amphetamines↗

PubMed1990

Dissociation constants and relative efficacies estimated from the functional antagonism of beta-adrenoceptor agonists on transmural stimulation in rat vas deferens.

In rat vas deferens, the beta-adrenoceptor agonists, isoprenaline, salbutamol, terbutaline and fenoterol, inhibited the contractions elicited by transmural electrical stimuli to an extent which depended on voltage magnitude. The dose-response curves for these agonists were shifted slightly to the right when the amplitude of the twitch was increased up to twice its original size. Consequently, the values of pD2 for the respective agonists obtained with a '50% twitch' and a '100% twitch' were: 7.6 and 7.5, 6.8 and 6.6, 6.2 and 6.0, 7.6 and 7.4. In addition, the maximal effects of the agonists were significantly reduced (by 13-18%). The values of other parameters for the same agonists, calculated according to a model for functional antagonism, were: negative log of dissociation constants (pKa): 7.2, 6.3, 6.2 and 7.2; percent receptors occupied to induce a half-maximal effect (y50): 42, 46, 63, and 53; relative intrinsic efficacy (er): 1.0, 0.9, 0.7, and 0.8. The usefulness of this type of functional antagonism as an alternative method for the estimation of drug-receptor parameters is discussed in the light of receptor theory.

Adrenergic beta-Agonists↗

PubMedDate not supplied

Morphometric and immunocytochemical study of the fetal, infant, and adult human vas deferens.

The human vas deferens (VD) is often considered simply as a conduit to transfer mature sperm from the epididymis to the ejaculatory duct. The cells that make up the epithelium of the VD, however, exhibit many characteristics of cells found in more complex epithelia, which are involved in absorption and/or secretion. In the present investigation, morphometry was utilized to characterize in detail the changes incurred by the human VD during its development, growth, and aging and to determine if these changes correlate with testicular maturation. In addition, the specific types of keratins present in the epithelial cells were defined, as well as desmin distribution in the muscular layers, during the various phases of the development, growth, and involution of the human VD. Results of the morphometric study are consistent with the interpretation that the development, growth, and aging of the VD are delayed, but parallel to, the identical phases exhibited by the human testis. Further, a differential expression of distinct keratin types was observed in the VD during the various phases examined in this study. Taken together, these two correlations may suggest that the VD is unlikely to function solely as a conduit for sperm. The rationale for this interpretation is as follows: 1) the complex developmental and maturational changes measured in the present investigation in the human VD are common to other absorptive and/or secretory epithelia; and 2) these changes parallel developmental changes observed in other androgen-dependent epithelia of the male reproductive tract, which also function to contribute components to seminal fluid as well as to provide a conduit for sperm.

Adolescent↗

PubMed1983

Pharmacological characterization of purinergic receptors in the rat vas deferens.

Using the isolated rat vas deferens, we have confirmed the existence of P1 purinergic receptors whose activation results in an inhibition of the neurogenic twitch of the vas deferens. The observed order of potency for agonists (adenosine ethyl carboxamide greater than 2-chloroadenosine greater than adenosine greater than 5'-AMP greater than 5'-ADP greater than ATP) and antagonism of these effects by theophylline supports a P1-mediated response. Metabolically stable analogs of ATP elicited dose-dependent contractile responses which were quantitatively greater than, but qualitatively comparable to, ATP-induced responses. The order of potency for the eliciting contraction was the following: adenylyl-5-imidodiphosphate = beta-gamma-methylene ATP greater than adenosine tetraphosphate much greater than ATP greater than ADP. Interestingly, these compounds also produced an inhibition of the neurogenic twitch with a similar rank order of potency. This response was not due to the activation of P1 receptors insofar as high concentrations of theophylline failed to attenuate either the inhibition of the neurogenic twitch or the contractile response induced by these agonists. Thus, these data demonstrate the presence of both P1 and P2 purinergic receptors in the rat vas deferens. In addition, the data are consistent with the idea that two distinct classes of P2 receptors exist in this tissue. Furthermore, these data suggest that the rat vas deferens provides a useful tissue for studying compounds which interact with both major subtypes of purinergic receptors.

Adenosine↗