The interrelationship between chloride ions and endothelium on alpha(1)-adrenoceptor-mediated contractions in aortic rings from Dahl normotensive and hypertensive rats

OBJECTIVES: The effects of chloride-free buffer in the absence or presence of the nitric oxide synthase inhibitor, N(omega)-nitro-L-arginine methyl ester (L-NAME), or chloride channel antagonist, indanyloxyacetic acid 94 (IAA-94) on alpha(1)-adrenoceptor mediated contractions were investigated in aortic rings from Dahl salt-resistant normotensive (SRN) and salt-sensitive hypertensive (SSH) rats on a 4% salt diet. METHODS: Systolic and diastolic blood pressure were measured via intra-arterial catheters under halothane anesthesia. Subsequently, the aorta was removed and cirazoline-induced contractions were recorded in normal Krebs and chloride-free buffer using ring preparation. Guanosine 3',5'-cyclic monophosphate (cyclic GMP) content of aortic rings was also determined by scintillation proximity assay kits. RESULTS: Systolic and diastolic blood pressure of SSH (180/130+/-1/1, mean+/-S.E.; n=14) were significantly higher than those of SRN (101/76+/-1/1, mean+/-S.E.; n=14) 7 weeks after they were placed on a salt diet. While the presence of L-NAME failed to have any impact on cirazoline-induced contractions in aortic rings from SSH rats, it significantly accentuated the effects of cirazoline in tissues from SRN rats. On the other hand, IAA-94 was able to inhibit cirazoline-mediated contractions in aortic rings from both SRN and SSH rats. The removal of chloride ions potentiated contractions produced by cirazoline in tissues from SRN but not SSH rats. Moreover, cirazoline-evoked responses in tissues from SRN were not further accentuated by the inclusion of L-NAME in chloride-free buffer. Cirazoline-mediated contractions in tissues from SSH rats were not influenced by absence of chloride ions, and the presence of L-NAME. It was also apparent that the inclusion of IAA-94 in absence of chloride ions did not prevent the potentiation of responses to cirazoline. Removal of chloride ions did not significantly decrease basal cyclic GMP levels in aortic rings from either strain. CONCLUSIONS: Basal release of nitric oxide seems to make a greater contribution in the suppression of cirazoline-evoked contractions in vessels from SRN as opposed to SSH rats. Chloride channels appear to contribute to cirazoline-evoked contractions in normal Krebs but not in chloride-free buffer.     

Quiet resting is not necessary prior to routine antenatal blood pressure measurement

A premeasurement period of 5 minutes quiet resting is recommended prior to measuring blood pressure. The aim of this study was to determine the effect of this period of rest on the level of blood pressure in pregnant women. One hundred pregnant women had their blood pressure measured on a single visit using a QuietTrak ambulatory blood pressure monitor, used to remove human observer bias. Group 1 (n = 50) had blood pressure measured as soon as possible on entering the clinic room and again after 5 minutes rest. Group 2 were rested for 5 minutes on entry to the clinic room prior to the first blood pressure measurement and had the second measurement taken after a further 5 minutes rest. Results were compared in the 2 groups using ANOVA. In Group 1, the initial, mean systolic blood pressure was 116.6 versus 115.5 mmHg taken after 5 minutes quiet rest (p = 0.66). The corresponding diastolic values were 66.2 versus 64.1 (p = 0.40). In Group 2, the initial mean systolic blood pressure was 116.2 versus 115.6 taken after 5 minutes quiet rest (p = 0.85). The corresponding diastolic values were 68.5 versus 65.6 (p = 0.34). Blood pressure was as likely to rise as to fall after a period of quiet rest. It is not necessary to have pregnant women quietly resting during routine visits before having blood pressure measured.     

抗真菌药物的研究II.C-端含氧代赖氨酸二肽的合成及抗白念珠菌活性

引用违法传递概念设计合成了11个C-末端含氧代赖氨酸二肽,进行抗深部致病菌-白念珠菌活性试验,体外实验结果显示极强的抑菌活性,MIC在12.5～0.8μg/disk之间,较母体氧化赖氨酸大50～135倍(克分子比。     

The release of β-endorphin and the neuropeptide-receptor mismatch in the brain

Microprobes bearing immobilized antibodies to the carboxy-terminus of β-endorphin were used to study the release of β-endorphin in the urethane anaesthetized rat following electrical stimulation of the ipsilateral arcuate nucleus. The microprobes were inserted through the cerebral hemisphere, the superior colliculus and the midbrain periaqueductal grey. Since such microprobes detect extracellular molecules along their entire length they give information on the persistence and spread of compounds following release. Little immunoreactive-β-endorphin was detected in the areas of brain sampled during electrical stimulation of arcuate nucleus but a remarkable spread throughout the midbrain and cerebral cortex occurred within 30 min of the cessation of stimulation. The results suggest that although β-endorphin-containing fibres are absent in many parts of the brain, this neuropeptide can access receptors in these sites and it is not necessary for release to be directly adjacent to opiate receptors. As such it is important evidence supporting the hypothesis of volume transmission as a means of neuronal communication. The results also suggest that an important mechanism of the transport of β-endorphin is the cerebrospinal fluid.