Comparative effects of angiotensin II and angiotensin-(4-8) on blood pressure and ANP secretion in rats

Angiotensin II (Ang II) is metabolized from N-terminal by aminopeptidases and from C-terminal by Ang converting enzyme (ACE) to generate several truncated angiotensin peptides (Angs). The truncated Angs have different biological effects but it remains unknown whether Ang-(4-8) is an active peptide. The present study was to investigate the effects of Ang-(4-8) on hemodynamics and atrial natriuretic peptide (ANP) secretion using isolated beating rat atria. Atrial stretch caused increases in atrial contractility by 60% and in ANP secretion by 70%. Ang-(4-8) (0.01, 0.1, and 1 µM) suppressed high stretch-induced ANP secretion in a dose-dependent manner. Ang-(4-8) (0.1 µM)-induced suppression of ANP secretion was attenuated by the pretreatment with an antagonist of Ang type 1 receptor (AT₁R) but not by an antagonist of AT₂R or AT₄R. Ang-(4-8)-induced suppression of ANP secretion was attenuated by the pretreatment with inhibitor of phospholipase (PLC), inositol triphosphate (IP₃) receptor, or nonspecific protein kinase C (PKC). The potency of Ang-(4-8) to inhibit ANP secretion was similar to Ang II. However, Ang-(4-8) 10 µM caused an increased mean arterial pressure which was similar to that by 1 nM Ang II. Therefore, we suggest that Ang-(4-8) suppresses high stretch-induced ANP secretion through the AT₁R and PLC/IP₃/PKC pathway. Ang-(4-8) is a biologically active peptide which functions as an inhibition mechanism of ANP secretion and an increment of blood pressure.

Effect of H2 S system on space learning and memory ability in PTSD model rat and on the frequency of spontaneous discharges of hippocampus neurons / 中国药理学通报

Aim To explore the behavior and CBS /H2 S levels of hippocampus in post traumatic stress dis-order (PTSD)rats and study the effect of exogenous H2 S on PTSD rats.Methods Single prolonged stress paradigm was adopted to prepare PTSD animal model. Morris water maze test was adopted to test space learn-ing and memory ability.CBS /H2 S content in hippo-campus tissue sample was measured using Western blot and methylene blue method.In vivo extracellular single unit recording was used to examine the frequency of spontaneous discharges of hippocampus neurons.Re-sults ① Escape latency increased and quadrant time (%)and platform crossing times decreased in Morris water maze test of PTSD group compared with normal group(P <0.01 ).CBS /H2 S level in hippocampus tis-sue of PTSD group also decreased compared with nor-mal group (P <0.01 ,P <0.05 ).② Escape latency decreased and quadrant time(%)and platform cross-ing times increased in Morris water maze test of NaHS+PTSD group compared with PTSD group(P <0.01 ).③ L-cysteine increased the frequency of spontaneous discharges of hippocampus neurons(P < 0.01 ).Con-clusions Learning and memory ability decrease in PTSD model rats owing to the inhibition of CBS /H2 S content in hippocampus tissue.The mechanism of be-havior improvement of H2 S on PTSD model rat is possi-bly related to the excitation of H2 S on frequency of spontaneous discharges of hippocampus neurons.

Difference of CD3+CD4+and CD3+CD8+T cells between patients with advanced small cell lung cancer and non-small cell lung cancer / 中国免疫学杂志

Objective:To investigate the difference of CD3+CD4+and CD3+CD8+T cells between patients with advanced small cell lung cancer and with non-small cell lung cancer, and provide available reference for treatment.Methods: Peripheral blood was taken from 65 patients with advanced lung cancer which was included 14 cases of small cell lung cancer and 51 cases of non-small cell lung cancer, 20 cases normal controls.The expression of CD3+CD4+ and CD3+CD8+ on lymphocytes was analyzed with flow cytometry.Results:We found that the percentage of CD3+CD4+T cells in small cell and non-small cell lung cancer patients were both much less than that of normal controls.There was no significant variation in the percentage of CD3+CD8+T cells between advanced lung cancer patients and normal controls.CD4+/CD8+in patients with advanced small cell lung cancer were a lot less than those in normal controls.Conclusion:Both of the percentage of CD3+CD4+T cells in small cell and non-small cell advanced lung cancer patients were significantly decreased than that in normal controls.Patients who attacked with advanced lung cancer were severely injured in cellular immunity.

Application of teaching method of case-based learning into physiology education of clinical medical undergraduates / 中华医学教育探索杂志

According to the advantages and disadvantages of the clinical medical educa-tion of the ordinary specialized subject-to-undergraduate,the traditional teaching method has been improved in two aspects:choosing case and teaching process.It can be conformed that teaching method of case-based learning is very suitable for physiological teaching.It can improve the effective interaction of teachers and students,and enchance the students' abilities of self-study and theory with practice.