Effects of calcitonin gene-related peptide (CGRP) on Ca2+-channel current of isolated smooth muscle cells from rat vas deferens

Summary Effects of calcitonin gene-related peptide (CGRP), a putative non-adrenergic non-cholinergic neutrotransmitter on the electrical properties of the cell membrane, were investigated in enzymically dispersed smooth muscle cells from rat vas deferens. Under current clamp conditions, CGRP (up to 10^–7 M) did not induce significant changes in membrane potentials or input resistance in the resting state. The configurations of action potentials elicited by depolarizing current pulses were also unaffected, except that a prolongation of the duration of the action potentials by a high dose (10^–7 M) of CGRP was observed in some of the cells. Under whole cell voltage clamp conditions, the transient and sustained K⁺ currents, activated by depolarizing voltage-steps, were apparently decreased in the presence of 10^–9 to 10^–7 M CGRP. The peptide increased the voltage-gated Ca²⁺ current in cells loaded with 145 mM Cs⁺ solution in order to block the K+ currents. The voltage-dependency of the peak Ca²⁺ current was not changed by CGRP. Ba²⁺ (10.8 mM) was used as a charge carrier for the Ca²⁺-channel current to clarify further the effects of CGRP on the properties of the current. CGRP (10^–8 M) delayed the inactivation time course of the Ca²⁺-channel current and slowed the recovery from inactivation. The peptide did not affect the steady-state inactivation measured by changing the holding potential. The Ca²⁺-channel current in the presence of CGRP was suppressed by nicardipine (10^–6 M) to the same extent as the current under control conditions. The results suggest that CGRP modifies the L-type Ca²⁺ channel in smooth muscle cells. Correspondence to N. Matsuki at the above address     

应用双线悬吊法行兔输精管吻合术的实验研究

目的 应用双线悬吊法行兔输精管吻合术,并探讨其安全性和有效性.方法 将30只雄性新西兰白兔随机分为3组,Ⅰ组在剪断输精管后即刻行双线悬吊法输精管吻合术,即以10 -0无创伤缝合线行输精管全层缝合两针,牵引缝线使两侧输精管断端无张力、无扭曲对合,牵引线缝出皮肤,打结固定于切口,10天后抽出牵引线.Ⅱ组和Ⅲ组分别在输精管...     

Non‐classic cystic fibrosis associated with D1152H CFTR mutation

Burgel P‐R, Fajac I, Hubert D, Grenet D, Stremler N, Roussey M, Siret D, Languepin J, Mely L, Fanton A, Labbé A, Domblides P, Vic P, Dagorne M, Reynaud‐Gaubert M, Counil F, Varaigne F, Bienvenu T, Bellis G, Dusser D. Non‐classic cystic fibrosis associated with D1152H CFTR mutation. Background: Limited knowledge exists on phenotypes associated with the D1152H cystic fibrosis transmembrane conductance regulator (CFTR) mutation. Methods: Subjects with a D1152H allele in trans with another CFTR mutation were identified using the French Cystic Fibrosis Registry. Phenotypic characteristics were compared with those of pancreatic insufficient (PI) and pancreatic sufficient (PS) cystic fibrosis (CF) subjects in the Registry (CF cohort). Results: Forty‐two subjects with D1152H alleles were identified. Features leading to diagnosis included chronic sinopulmonary disease (n = 25), congenital absence of the vas deferens (n = 11), systematic neonatal screening (n = 4), and genetic counseling (n = 2). Median age at diagnosis was 33 [interquartile range (IQR, 24–41)] years in D1152H subjects. Median sweat chloride concentrations were 43.5 (39–63) mmol/l in D1152H subjects and were markedly lower than in PI and PS CF subjects (p < 0.05). Bronchiectasis was present in 67% of D1152H subjects, but Pseudomonas aeruginosa colonization and pancreatic insufficiency were present in <30% of subjects. Estimated rates of decline in forced expiratory volume in 1 s (FEV₁) were lower in D1152H subjects vs PI CF subjects (p < 0.05). None of the D1152H subjects identified since 1999 had died or required lung transplantation. Conclusions: When present in trans with a CF‐causing mutation, D1152H causes significant pulmonary disease, but all subjects had prolonged survival.     

Dual excitatory actions of acetylcholine at the neuromuscular junction in the guinea-pig vas deferens

The action of acetylcholine (ACh) on the smooth muscle of guinea-pig vas deferens was studied using the sucrose-gap method. ACh, when applied at a concentration of 10^–6 M, evoked a depolarization of the smooth muscle membrane which was slow in time course (slow depolarization). When ACh was applied at higher concentrations, another depolarization which was fast in time course (fast depolarization) occurred, overlapping the early part of the slow depolarization. The magnitudes of both depolarizations were concentration-dependent on ACh. TTX and adrenergic receptor antagonists had little effect on either depolarizations, while guanethidine and nicotinic receptor antagonists mainly suppressed the fast depolarization. In contrast, atropine suppressed the slow depolarization. The membrane conductance observed by current application, was reduced during the slow depolarization, and the reversal potential of the depolarization was 18.3 mV negative to the resting membrane potential. Whereas, the reversal potential of the fast depolarization was 27.6 mV positive to the resting membrane potential. This reversal potential was quite similar to that of the adenosine triphosphate (ATP)-induced depolarization, previously observed in the same tissue. From these observations, it is suggested that in the guinea-pig vas deferens, ACh acts on nicotinic receptors at the sympathetic postganglionic nerve terminal, causing the release mostly of a non-adrenergic transmitter, probably ATP. In addition, ACh also acts on muscarinic receptors on the smooth muscle membrane, inducing membrane depolarization resulting from a reduction of the membrane conductance to potassium ions.     

Volume-sensitive chloride currents in primary cultures of human fetal vas deferens epithelial cells

Using the patch-clamp technique, we have identified a large, outwardly rectifying, Cl⁻-selective whole-cell current in primary cultures of human vas deferens epithelial cells. Whole-cell currents were time- and voltage-dependent and displayed inactivation following depolarising pulses ≥ 60 mV. Currents were equally permeable to bromide (P _Br/P _Cl = 1.05 ± 0.04), iodide (P _I/P _Cl = 1.06 ± 0.07) and Cl⁻, but significantly less permeable to gluconate (P _Gluc/P _Cl = 0.23 ± 0.03). Currents spontaneously increased with time after establishing a whole-cell recording, but could be inhibited by exposure to a hypertonic bath solution which reduced inward currents by 68 ± 4%. Subsequent exposure of the cells to a hypotonic bath solution led to a 418 ± 110% increase in inward current, indicating that these currents are regulated by osmolarity. 4,4′-Diisothiocyanatostilbene-2,2′-disulphonic acid (100 μM) produced a rapid and reversible voltage-dependent block (60 ± 5% and 10 ± 7% inhibition of current, measured at ± 60 mV, respectively). Dideoxyforskolin (50 μM) also reduced the volume-sensitive Cl⁻ current, but with a much slower time course, by 41 ± 13% and 32 ± 16% (measured at ± 60 mV, respectively). Tamoxifen (10 μM) had no effect on the whole-cell Cl⁻ current. These results suggest that vas deferens epithelial cells possess a volume-sensitive Cl⁻ conductance which has biophysical and pharmacological properties broadly similar to volume-sensitive Cl⁻ currents previously described in a variety of cell types. Received: 25 January/Accepted: 25 April 1996     

睾丸体积与输精管大小的活体测量

用木制的睾丸模型测量子,测定了要求作输精管结扎术的305例广东地区生育力正常男子609个睾丸的体积,结果是14.4±3.1ml,左右睾丸无显著差异.在305例中切出了170条输精管,在显微镜下进行了测量,外径为2.3±0.3mm,内径为0.5±0.1mm,相应的睾丸体积与输精管内、外径无显著相关.     

先天性单侧输精管缺如患者CFTR基因突变研究

目的 探讨囊性纤维跨膜转运调节物（ｃｙｓｔｉｃ ｆｉｂｒｏｓｉｓ ｔｒａｎｓｍｅｍｂｒａｎｅ ｃｏｎｄｕｃｔａｎｃｅ ｒｅｇｕｌａｔｏｒ,ＣＦＴＲ）基因在中国人先天性单侧输精管缺如（ｃｏｎｇｅｎｉｔａｌ ｕｎｉｌａｔｅｒａｌ ａｓｅｎｃｅｏｆ ｔｈｅ ｖａｓ ｄｅｆｅｒｅｎｓ,ＣＵＡＶＤ）患者中的突变频率及热点。方法 应用聚合酶反应－单链构象多态（ＰＣＲ－ＳＳＣＰ）、３银染技术及ＰＣＲ产物直接序     

Roles for α1-adrenoceptors during contractions by electrical field stimulation in mouse vas deferens

We have investigated the relative roles of α₁-adrenoceptors and purinoceptors in contractions to low and high frequency stimulation of the mouse vas deferens, in terms of the time course of responses. In separate experiments, isometric contractile responses were obtained to 10 pulses at 1 Hz and 40 pulses at 10 Hz. Responses to 1 Hz stimulation consisted of a series of discrete peaks. The α_1A-adrenoceptor antagonist RS100329 (10^–9M–10^–7M) significantly reduced the response to the first pulse, the α_1D-adrenoceptor antagonist BMY7378 (10^–7M–10^–6M) significantly reduced the response to the first two pulses, and the non-selective α₁-adrenoceptor antagonist prazosin (10^–8M) reduced the response to the first 4 pulses at 1 Hz. Responses to 10 Hz stimulation consisted of an early peak response and a maintained plateau response. RS100329 significantly reduced the peak response but did not significantly affect the plateau response. Prazosin, significantly reduced both the peak and plateau responses. The α_1A-adrenoceptor antagonist RS17053 in high concentrations reduced mainly the plateau response leaving a clear early peak response. The plateau response of contraction was almost abolished by the purinoceptor antagonist suramin. These results suggest that there is a relatively minor early α_1D-adrenoceptor and a larger early α_1A-adrenoceptor component to stimulation-evoked contractions of mouse vas deferens, but the major α₁-adrenoceptor component is revealed by prazosin to be α_1B-adrenoceptor mediated. α_1B-Adrenoceptor activation probably facilitates contractions mediated by other α₁-adrenoceptors and by purinoceptors. These results suggest that combined non-selective α₁-adrenoceptor blockade, particularly α_1B-adrenoceptor blockade, in addition to P2X1-purinoceptor blockade is useful in reducing male fertility.