Effects of osmotic pressure and brain-derived neurotrophic factor on the survival of postnatal hypothalamic oxytocinergic and vasopressinergic neurons in dissociated cell culture

Neurons from hypothalamic paraventricular nuclei (PVN) and supraoptic nuclei (SON) from postnatal day 6-8 rats were enzymatically dissociated and separately maintained in monolayer cultures for 14 days. The osmotic pressure of the culture medium, based on Neurobasal medium (Life Technologies), was varied (255, 300 and 330 mOsm/l) by adjustment using mannitol. The survival of oxytocin (OT), vasopressin (VP) and oxytocin-vasopressin (OT/VP) coexpressing neurons were studied under these varied conditions, and the identification of the cell phenotypes in the cultures was carried out by using double-label immunofluorescence. Under control osmolar conditions (300 mOsm/l) equivalent numbers of OT and VP neurons were found in the SON (P = 0.8398) and PVN (P = 0.4721) cultures. The OT neurons' survival did not change in 255 or 330 mOsm media in the SON cultures, but the VP neurons in the SON cultures were significantly increased in 255 mOsm/l medium as compared to control (300 mOsm/l) medium (P = 0.0088). No significant changes were found in VP neuron survival in SON cultures between the 300-330 mOsm/l media (P = 0.2372). Similar data were obtained for the VP neurons in PVN-derived cultures, but the OT neurons in these cultures survived significantly better at 300 mOs/l than at 255 mOsm/l (P<0.0001), but were not significantly different at 330 mOsm/l (P = 0.1208). In general, the VP neurons were more vulnerable than OT neurons to increases of culture medium osmolarity with respect to their survival. The number of OT/VP coexpressing neurons was greater in SON-derived cell cultures as compared to PVN-derived cell cultures, and their numbers were higher in the lower osmolarity media. The effects of adding brain-derived neurotrophic factor (BDNF) to the culture medium on survival were determined. BDNF significantly increased the numbers of all three types of neurons in both PVN and SON cell cultures (P = 0.0001-0.0060). The phenotypically identified cells, cultured in the 300 mOsm/l medium, responded by depolarization or hyperpolarization when transferred to hypertonic or hypotonic perfusion salines, respectively.     

Activity of vasopressinergic neurones of the human supraoptic nucleus is age- and sex-dependent

In the human hypothalamus, arginine-vasopressin (AVP) is produced for a major part by the neurones of the supraoptic nucleus (SON). Since plasma AVP levels in men were reported to be higher than those of women and we did not find a sex difference in the neurone number, a higher vasopressinergic neurone activity was supposed to be present in the SON of men. Therefore we studied the size of the Golgi-apparatus (GA), which has been demonstrated previously to be a sensitive parameter for protein synthetic ability of neurones, in 15 men and 17 women ranging in age from 29 to 94 years. A polyclonal antibody against immunoaffinity purified MG-160, a sialoglycoprotein of the medial cisternae of the GA was applied on paraffin-embedded sections containing the dorsolateral SON (dl-SON) from which 90-95% of neurones are vasopressinergic. SON areas that contain oxytocin (OT) cells were excluded on the basis of adjacent sections stained with a monoclonal antibody against OT. By means of an image analysis system the size of the GA and the cellular profile area were determined in dl-SON neurones with a nucleolus. Our results showed indeed an age-dependent sex difference in the size of the GA that appeared to be twice as large in young men (< or = 50 years old) than in young women of the same age. The size of the GA increased with age in women but not in men. In addition, the mean cell profile area, another measure for neuronal activity, was significantly larger in young men than in young women and was in old women larger than in young women. In conclusion, these data show the presence of a sex-dependent age-difference in the activity of vasopressinergic neurones in dl-SON which may relate to differences in AVP and sex hormone levels and kidney AVP receptors.     

Spike conduction properties of T-shaped C neurons in the rabbit nodose ganglion

Noradrenaline (NA) and angiotensin II (A II) were infused intravenously in conscious dogs without (series I) and with (series II) additional infusions of sodium nitroprusside at doses re-establishing normal levels of mean arterial pressure (MAP). In series I, NA infusion (1.6 g/min per kg for 30 min) initially elevated MAP by some 25 mm Hg and lowered heart rate by some 30 beats/min. Plasma concentrations of arginine vasopressin (AVP) remained constant, while those of A II and atrial natriuretic factor were slightly, but significantly, increased. Infusion of A II (10 or 20 ng/min per kg for 30 min) induced similar rises in MAP and slight reductions of heart rate and increased plasma AVP by 70% and atrial natriuretic factor by 60%. In series II, sodium nitroprusside (1–4 g/min per kg) was added for 30 min to infusions of NE (1.6 g/min per kg) and A II (20 ng/min per kg) in order to maintain MAP at its control level. This resulted in an 11-fold increase in plasma AVP during NA infusion and a 19-fold increase during A II infusion. Infusing sodium nitroprusside (4 g/min per kg) alone lowered MAP to clearly hypotensive levels, but the resulting rises in plasma AVP were less than, rather than equal to, those seen at normotensive MAP levels during the combined infusions of sodium nitroprusside with A II or NA, respectively. It is concluded that both NA and A II exert strong stimulatory actions on AVP release which are, however, counteracted by inhibitory influences arising from the hypertensive effects of NA and A II.     

精氨酸、尼莫地平、细胞生长肽对环孢素毒性及其血药浓度的影响

目的：探讨精氨酸、尼莫地平、细胞生长肽(bFGF)对环孢素的肝、肾、睾丸毒性的防护作用和对体内药物浓度的影响。方法：雄性大鼠给予环孢素后，再分别给予精氨酸、尼莫地平和bFGF，测定大鼠环孢素浓度、细胞凋亡指数、血清谷丙转氨酶(ALT)、肌肝(Cr)、生精功能等。结果：精氨酸明显升高大鼠血中环孢素浓度，尼莫地平和bFGF则降低环孢素浓度。精氨酸、尼莫地平和bFGF具有明显降低肝、肾、睾丸细胞凋亡指数、血清ALT和Cr，以及减轻精子发生障碍的作用。结论：精氨酸、尼莫地平、bFGF可影响血中环孢素浓度，并减轻环孢素引起肝、肾、睾丸的毒性，而以精氨酸的作用较明显。     

AccQ-Tag法测定复方精氨酸胶囊中精氨酸的含量

目的：建立测定复方精氨酸胶囊中精氨酸含量的AccQ—Tag法^[1,2,3]。方法：以6-氨基喹啉-N-羟基琥珀酰亚胺基甲酸酯(AQC)为衍生剂，与复方精氨酸胶囊中精氨酸柱前定量衍生，用Waters HPLC仪，AccQ—Tag^TM氨基酸分析柱，以pH4．95醋酸钠缓冲液为流动相A，乙腈—水(3：2)为流动相B，进行梯度洗脱，检测波长为248nm。结果：线性范围：0．1006～0．9054μg，r=0．9995(n=5)。回收率：99．7％，RSD0．38％(n=5)。结论：本法快速、简便，辅料无干扰，结果满意。     

Poloxamer gel as vehicle for transdermal iontophoretic delivery of arginine vasopressin: evaluation of in vivo performance in rats

The present study describes the formulation and evaluation for pharmacokinetic and pharmacodynamic activity of arginine vasopressin (AVP), a nanopeptide with antidiuretic activity on being delivered by transdermal iontophoresis. Poloxamer 407 was used to form stable gels that did not reduce the release of AVP. The release rate from the gel followed Higuchi kinetics indicating that the dominant mechanism of release is diffusion. Iontophoresis alone and in combination with chemical enhancers was used to augment the transdermal permeation of AVP. The results of both pharmacokinetic and pharmacodynamic studies emphasize the dimension of 'rapid onset' achieved by iontophoresis. The correlation between pharmacokinetic data and pharmacodynamic activity was only qualitative. Histopathological studies revealed that skin toxicity caused by either iontophoresis or chemical enhancers when used alone could be reduced by using a combination of both the techniques in tandem.     

高效液相色谱-蒸发光散射检测法测定中药板蓝根中精氨酸的含量

目的 :建立中药板蓝根中精氨酸的含量测定方法。方法 :以LunaC1 8(4 6mm× 15 0mm ,5 μm)色谱柱为固定相 ,柱温2 5℃ ;以水 三氟醋酸 (99 8∶0 2 )为流动相 ,流速 0 2ml·min- 1 ;蒸发光散射检测器检测 ,漂移管温度 10 5℃ ,气体流速 3 0 0L·min- 1 。结果 :精氨酸在 0 5 0 4 μg～ 2 5 2 μg范围内线性关系良好 ,r=0 9992。平均加样回收率为 99 3% ,RSD =0 9% (n =5 )。结论 :该方法简便、准确 ,重复性好。     

阿司匹林精氨酸盐注射液的制备及其稳定性研究

目的　制备阿司匹林精氨酸盐及其注射液 ,并测定含量 ,考察稳定性。方法　阿司匹林与精氨酸反应生成阿司匹林精氨酸盐 ,精制后以注射用水为溶剂制成阿司匹林精氨酸盐注射液 ,用紫外 -可见分光光度法测定其含量 ,考察阿司匹林精氨酸盐及其注射液在 30 ,4 5 ,6 0℃及 30 ,35 ,4 0 ,4 5℃的稳定性。结果　阿司匹林精氨酸盐在高温下不稳定 ,初步确定其注射液的有效期为 1.32年。结论　阿司匹林精氨酸盐及其注射液制备方法可行 ,其原料及制剂在常温下稳定     

血管加压素对酒精戒断大鼠下丘脑-腺垂体-肾上腺皮质功能的影响

目的:观察在长期低浓度酒精处理及酒精戒断过程中,大鼠血浆中血管加压素(AVP)、促肾上腺皮质激素(ACTH)和皮质醇含量的变化以及下丘脑中AVP、促肾上腺皮质激素释放因子(CRF)含量的变化,进而探讨酒精对机体应激水平的影响以及AVP在酒精依赖过程中的作用。方法:以6%(V/V)的酒精作为大鼠饮水的唯一来源,分别饮酒1、3、7、14、21、28d,以及饮酒28d后撤除酒精2h,取不同处理大鼠的血浆和下丘脑标本,采用放射性免疫测定法分别测定CRF、AVP、ACTH和皮质醇水平;气相色谱法测定大鼠在饮酒过程中不同时段血中酒精浓度。结果:大鼠饮酒3d后,血浆中的AVP和皮质醇水平显著增高,并持续至饮酒结束,而血浆ACTH水平无明显变化。使用AVP受体拮抗剂后,血液中ACTH和皮质醇含量显著下降。动物血中酒精浓度在摄入酒精的不同时段无明显差异。结论:长时程的低浓度酒精刺激使机体应激水平升高,同时下丘脑-腺垂体-肾上腺皮质轴功能紊乱,这可能是动物产生酒精依赖的重要原因之一。     

HPLC-ELSD法测定盐酸精氨酸片含量

本文建立一种快速、准确的HPLC-ELSD法测定盐酸精氨酸的含量的方法.色谱柱:Lichrospher100 RP-18;流动相: 0.1%三氟醋酸-乙腈(60:40). 盐酸精氨酸在1.26μg～2.92μg范围内进样量与峰面积的对数具有良好线性关系(r=0.9995);盐酸精氨酸平均回收率为:100.2%,RSD为:0.67%(n=9).本法快速,简便,准确,重现性好.