大鼠输精管滤过装置节育术的实验研究

本文目的是观察SD大鼠双侧输精管植入滤过装置的节育效果,以及远期局部输精管的组织病理学变化,并对装置内部进行扫描电镜观察。结果装置组8只动物全部失去生育力,交配后雌鼠阴栓内均未见到精子。半年后形态学研究表明装置近端有大量精子,输精管扩张,形成精子肉芽肿。扫描电镜发现装置尼龙丝被蛋白样颗粒物质包绕,装置内尼龙丝之间有一些精子,形态大多完整,少量精子可穿过装置到达装置远端,但形态不完整。本研究表明SD大鼠输精管植入滤过装置有可靠的节育效果,滤过装置能阻止大部分精子通过。附睾液和少量精子可通过装置,但精子形态不完整,失去受精能力。滤过装置的节育机理尚需进一步深入研究。     

兔输精管腔内压强与管壁组织学变化的相关性研究

目的：为探讨输精管腔内压强变化与管壁组织学变化的相关性。方法：本文采用计算机监控的智能注射装置，测量出兔输精管注射过程中压强变化曲线，并对曲线斜率变化显著的各点作组织学观察。结果：输精管腔内压强随管腔容量增加所产生的变化趋势呈固有模式，与个体特性无关；管壁组织学改变与管腔内压强变化幅度有明显的一致性，而与容量绝对值无明确的对应关系。结论：输精管腔内压强变化能更好地预测管壁组织学的相应改变，输精管注射节育时，采用测控压强的方法计算阻塞剂用量会更加精确可靠。     

Possible role of sildenafil in inhibiting rat vas deferens contractions by influencing the purinergic system

AIM: To evaluate the effect of sildenafil, a selective inhibitor of cyclic guanosine monophosphate (cGMP)-selective type 5 phosphodiesterase, on isolated rat vas deferens and its connections with the purinergic system. METHODS: Epididymal and prostatic portions of isolated vas deferens were placed in organ baths containing Krebs' solution. Contractions were induced by noradrenaline (NA), adenosine triphosphate (ATP), alpha,beta-methylene ATP and electrical field stimulation (EFS). The effect of sildenafil on the contractions was compared with suramin and Evans blue (EB). RESULTS: NA, ATP, alpha,beta-methylene ATP and EFS caused contractions in both portions of vas deferens. NA-induced contractions were unaffected by sildenafil and suramin but potentiated by EB. ATP-induced contractions were non-competitively inhibited in both portions by sildenafil and suramin but potentiated by EB. alpha,beta-methylene ATP-induced contractions were unaffected by sildenafil but were inhibited in both portions by suramin and EB. EFS-induced contractions were inhibited by sildenafil and suramin while potentiated by EB. CONCLUSION: Sildenafil inhibited the contractions in both portions of vas deferens, as did suramin. We have suggested that purinergic system has a role in this antagonism and it seems to be mediated by an ATP-dependent mechanism instead of a receptor interaction.     

Cystic fibrosis transmembrane conductance regulator (CFTR) gene mutation associated with a congenital bilateral absence of vas deferens

Abstract:   Cystic fibrosis transmembrane conductance regulator ( CFTR ) gene mutations associated with cystic fibrosis have been reported to be rare in Japanese patients with congenital bilateral absence of vas deferens (CBAVD).
A 28-year-old Japanese male was referred for infertility. Vas deferens and epididymis were not palpable bilaterally. Semen analyses showed azoospermia with volumes below 2.0 ml. Serum follicle-stimulating hormone value was slightly elevated. Seminal fructose concentration was also very low. Scrotal ultrasonography showed absence of the bodies and tails of the right and left epididymides. Imaging studies showed cystic dysplasia of the right seminal vesicle and agenesis of the left seminal vesicle. A CFTR gene mutation of I556V was found.
Recent studies show that prevalence of CFTR gene mutation in Japanese CBAVD patients may be approximately equal to that of the Caucasian population. Genetic counselling may be recommended for any couple attempting assisted reproduction technology when the man has CBAVD.     

Reserpine-induced potentiation of the inhibitory action of neuropeptide Y on the rat vas deferens neurotransmission

The inhibitory action of neuropeptide Y (NPY) on the muscular activity of the prostatic end of the rat vas deferens elicited by transmural electrical stimulation was examined in control and in reserpinized rats. Pretreatment with 1 mg/kg reserpine for 48 h induced a 6-fold increase in NPY potency. Likewise, the potency of clonidine to inhibit the electrically induced muscular activity or noradrenaline to contract the ductus musculature was also potentiated. It is hypothesized that reserpine via a denervation super-sensitivity-like process increases the density of the NPY receptors. The functional significance of NPY in the motor activity of the vas deferens is discussed.     

水通道蛋白亚型AQP1-9在雄性小鼠生殖系统mRNA的表达

目的：明确AQP1-9在雄性小鼠生殖系统的分布与表达。方法：应用RT-PCR技术检测AQP1-9在雄性小鼠生殖系统不同器官的表达。结果：在成年雄性小鼠的生殖系统中，有多种水通道的表达，睾丸中有AQP3、5、7、8、9表达；附睾头中有AQP3、6、8表达；附睾尾有AQP3、5、6、7、8表达；输精管中有AQP1、2、3、4、5、6、7的表达。结论：小鼠生殖系统中多种水通道蛋白的表达提示AQP与生殖功能有密切关系。     

A STUDY OF STIMULATION-EVOKED ACTIVATION OF α2-ADRENOCEPTORS IN THE RAT ISOLATED VAS DEFERENS

Experiments were performed with prostatic and epididymal segments of rat vas deferens to determine whether alpha 2-adrenoceptors in this organ were activated during field stimulation of sympathetic terminals with short trains of pulses applied at low frequencies. In prostatic segments the magnitude of twitches evoked by trains of ten field pulses at 1 or 2 Hz declined after 2-3 s of stimulation. In contrast, facilitation of twitches and fusion of contractions occurred when similar stimulation was applied to epididymal segments. In prostatic segments from rats treated with reserpine (2.5 mg/kg i.p.) 24 h previously, there was no decline in the magnitude of twitches produced by successive impulses in a train of stimulating pulses. In epididymal segments from reserpine-treated rats facilitation of twitches in response to successive impulses in each train still occurred. In prostatic segments cocaine (5 and 10 mumol/l) enhanced twitch fade with stimulation at 1 and 2 Hz without altering the time for onset of this effect. In epididymal segments cocaine led to enhancement and prolongation of contractile responses. In prostatic segments yohimbine (0.01-0.06 mumol/l) reduced or reversed the effect of cocaine in enhancing twitch fade. In preparations where the reversal of the effect of cocaine by yohimbine was incomplete, subsequent addition of phentolamine (1 mumol/l) produced complete reversal. In epididymal segments yohimbine (0.01 mumol/l) produced a further enhancement in the twitch responses to stimulation at 1 and 2 Hz. Subsequent addition of phentolamine (1 mumol/l) reversed the facilitatory effects of cocaine and yohimbine. Propranolol (10 mumol/l) was without effect upon responses to stimulation in either segment of rat vasa deferentia. These experiments indicate that noradrenaline, released by short trains of impulses applied at low frequency to hypogastric nerve terminals activates prejunctional alpha 2-adrenoceptors in the prostatic segment of the vas deferens. In the epididymal portion the effects arising from activation of prejunctional alpha 2-adrenoceptors are outweighed by the consequences of activation of extrajunctional alpha 1-adrenoceptors located on longitudinally arranged muscle.     

A model of an intraprostatic vas deferens in the rat

The study of the effect of hormones in seminal fluid upon prostate tissue is hampered by the lack of a suitable model. Such a model is described in this paper, and its possible usefulness is discussed. The vas deferens of the rat is moved from its normal position into a surgical incision into the ventral prostate. Squamous metaplasia of epithelium in prostatic acini at early stages is replaced by cuboidal epithelium. At later stages, normal-appearing glandular epithelium is seen as close as 50 micrometers to the vas deferens. The structure of the vas deferens is not affected.     

Effect of cGMP Derivatives on Contraction Relaxation Cycle,Release of Norepinephrine and Protein Kinase Activity in Guinea Pig Vas Deferens

Abstract: Contractions of the guinea pigs vas deferens were induced by field stimulation and the effects of derivatives of cGMP were tested on the contraction-relaxation cycle. Relaxation was induced by 8-Br-cGMP and O^2′-mb-cCMP. On the contrary, db-cGMP and N²-mb-cGMP potentiated the contraction. The relaxant effect of 8-Br-cGMPwas not mimiced by 8-Br-5′GMP, instead the latter caused the opposite effect. Since neither 8-Br-cGMP nor db-cGMP affected the release of norepinephrine on field stimulation the cGMP derivatives induced their effects at a postsynaptic site. 8-Br-cGMP was found to be 100-fold more potent than cGMP to stimulate protein kinase activity in crude extracts from guinea pig was deferens. N²-mb-cGMP and O^2′-mbcGMP were approximately equipotent to cGMP while db-cGMP was less active. 8-Br-5′-GMP did not stimulate the protein kinase. It is suggested that the results support the hypothesis that cGMP acts as a relaxant in the smooth muscle of the vas deferens. The potentiation caused by db-cGMP and N²-mb-cGMP on contractions could be dependent on the substitution in the guanine moiety of the molecules with the butyryl group. Their effect was thus probably unrelated to a specific cGMP effect.     

The effect of denervation on the synchronization of contraction of the rat vas deferens

Denervation of the rat vas deferens results in both quantitative and qualitative changes in the contraction of the isolated smooth muscle. The maximum contraction induced by norepinephrine, acetylcholine or serotonin is enhanced by a denervation. The response of the tissue to 2 × 10^?4 M BaCl₂ is also larger after denervation and in addition the character of the contraction is changed. In the denervated muscle BaCl₂ initiates a contraction which is more synchronized than the response of the control tissue. By use of ¹⁴C-sorbitol and Co-EDTA for estimating extracellular space and from fluorescence histochemical observations, it appears that facilitation of drug diffusion through the extracellular space plays an unimportant role in the altered response to drugs. In experiments which utilized a double-compartment tissue bath it was found that denervation enhanced the propagation of the contraction in the longitudinal direction. From measurements of the longitudinal tissue impedance it was determined that the resistance between smooth muscle cells was significantly decreased by denervation. These results suggest that denervation improves the propagation of excitation in this smooth muscle.