刺激大鼠迷走神经向中端对其不同脑区5-HT含量的影响

采用荧光分光光度法,测定脑内5-HT的含量,观察电刺激两侧颈迷走神经向中端对大鼠海马、下丘脑和中-桥脑内5-HT含量的影响,结果如下:(1)刺激迷走神经向中端后,三脑区的5-HT含量均显著增加(P<0.05-0.005);(2)侧脑室内注射新斯的明(10μg/10μl)或烟碱(10μg/10μl)后,刺激迷走神经向中端使三脑区5-HT含量增多的效应显著提高(p<0.01-0.001);(3)侧脑室内注射六烃季胺(250μg/10μl)后,刺激迷走神经向中端使三脑区5-HT含量增多的效应显著下降(p<0.05-0.005);(4)侧脑室内注射阿托品(10μg/10μl)或纳洛酮(10μg/10μl)后,不影响刺激迷走神经向中端引起的三脑区5-HT含量增多的效应(p>0.05)。由此看来,迷走传入冲动很可能先使脑内Ach释放增多,然后,Ach作用于N-胆碱受体而导致海马、下丘脑和中-桥脑内5-HT含量增加。以上结果表明,在脑内,迷走传入纤维和5-HT能神经元之间可能存在着机能联系。     

迷走神经背核的研究进展

迷走神经背核（ＤＭＶ）是一个重要的内脏运动核团和内脏感觉核团。ＤＭＶ与中枢及外周存在广泛的纤维联系。ＤＭＶ和孤束核、最后区一起构成了“迷走感觉运动中枢”。ＤＭＶ存在神经－体液回路,使ＤＭＶ神经元可以直接感受外周血及脑脊液中的信息。ＤＭＶ含乙酰胆碱、儿茶酚胺、神经肽类等多种递质及相应受体。ＤＭＶ参与中枢调节胃肠、心血管及内分泌等生理功能。     

脑室内注入TRH对大鼠肝胆生化影响机理的研究

在大鼠的脑室内注入ＴＲＨ（三肽酰胺）,观察其对大鼠肝胆汁分泌的影响．实验结果表明,侧脑室内注入ＴＲＨ对胆汁分泌量有明显的增强作用,并且随ＴＲＨ剂量加大其作用逐渐增强．而且在侧脑室内注入ＴＲＨ期间,胆汁中Ｋ＋、Ｃｌ－、Ｎａ＋、ＨＣＯ３－离子的排出量亦有增加．其机理在于,侧脑室内注入ＴＲＨ,激活中枢胆碱能系统,并通过送走神经而使肝的新陈代谢发生变化．     

Adrenal modulation of the inhibitory effect of corticotropin releasing factor on feeding

Corticotropin releasing factor (CRF) reduces food intake in rats after central administration. In these studies we examined whether the adrenal gland and the vagus were involved in CRF suppression of intake. One hour intake was reduced by a 5 μg (ICV) injection of CRF in sham but not adrenalectomized rats maintained on 0.9% NaCl. In a separate experiment on rats maintained on tap water, the inhibitory effect of CRF (5 μg) lasted at least 4 hours in sham rats whereas adrenalectomized rats did not significantly differ from controls. These experiments suggest that the adrenal gland modulates the feeding response to CRF. As replacement with corticosterone (0.75 mg/kg) in total adrenalectomized rats did not restore responsiveness to 5 or 10 μg of CRF, we next studied whether the adrenal medulla was responsible for the decreased responsiveness to CRF. In rats lacking the adrenal medulla only, food intake was reduced by a 5 μg injection of CRF; in sham rats, intake was significantly reduced by doses as low as 0.1 μg of CRF. An additional experiment examined the effect of gastric vagotomy on the CRF feeding response. Vagotomized rats were as responsive to 5 and 10 μg injections of CRF as sham rats, which suggests that the effect is not dependent on the vagus nerve. These findings indicate that the adrenal gland, primarily the medulla, plays an intermediate role in the reduction of food intake caused by central injections of CRF. This conclusion is consistent with the known effect of CRF on adrenomedullary discharge.     

The distribution and ultrastructure of sensory elements in the baroreceptor region of the truncus arteriosus of the lizard Trachydosaums rugosus

Summary The proximal truncus arteriosus of the lizard Trachydosaurus rugosus was studied with light-, fluorescence and electron-microscopical techniques. Three vessels comprised the truncus: the pulmonary, left aortic, and caroticoaortic arteries. Right and left truncal nerves, each derived from the ipsilateral vagus nerve, innervated the truncus, particularly its proximal 3 mm.Ultrastructurally, the nerves had a variety of appearances: some were clearly adrenergic, c-type or p-type. A number of profiles contained large numbers of mitochondria and were classified as sensory. Some profiles defied exact classification, having characteristics common to two different types of profile.Within the outer medial layers, profiles up to 7 m in diameter were found. These contained large numbers of mitochondria, myelin bodies and structures intermediate between the two. In addition, the profiles contained large amounts of glycogen and small numbers of vesicles. These nerve fibres were classified as baroreceptors, since they closely resemble carotid sinus and aortic arch baroreceptors in mammals.Large numbers of chromaffin cells were found, particularly in the common wall of the pulmonary and left aortic arteries. Many of these cells emitted a long tapering process, which sometimes entered a nearby nerve bundle. Sensory, p-type and c-type profiles, but not adrenergic profiles, made extensive close contacts with chromaffin cells.     

Preliminary Results of an Open Label Study of Heart Rate Variability Biofeedback for the Treatment of Major Depression

Major depressive disorder (MDD) is a common mood disorder that can result in significant discomfort as well as interpersonal and functional disability. A growing body of research indicates that autonomic function is altered in depression, as evidenced by impaired baroreflex sensitivity, changes in heart rate, and reduced heart rate variability (HRV). Decreased vagal activity and increased sympathetic arousal have been proposed as major contributors to the increased risk of cardiovascular mortality in participants with MDD, and baroreflex gain is decreased. STUDY OBJECTIVES: To assess the feasibility of using HRV biofeedback to treat major depression. DESIGN: This was an open-label study in which all eleven participants received the treatment condition. Participants attended 10 weekly sessions. Questionnaires and physiological data were collected in an orientation (baseline) session and Treatment Sessions 1, 4, 7 and 10. MEASUREMENTS AND RESULTS: Significant improvements were noted in the Hamilton Depression Scale (HAM-D) and the Beck Depression Inventory (BDI-II) by Session 4, with concurrent increases in SDNN, standard deviation of normal cardiac interbeat intervals) an electrocardiographic estimate of overall measure of adaptability. SDNN decreased to baseline levels at the end of treatment and at follow-up, but clinically and statistically significant improvement in depression persisted. Main effects for task and session occurred for low frequency range (LF) and SDNN. Increases in these variables also occurred during breathing at one's resonant frequency, which targets baroreflex function and vagus nerve activity, showing that subjects performed the task correctly. CONCLUSIONS: HRV biofeedback appears to be a useful adjunctive treatment for the treatment of MDD, associated with large acute increases in HRV and some chronic increases, suggesting increased cardiovagal activity. It is possible that regular exercise of homeostatic reflexes helps depression even when changes in baseline HRV are smaller. A randomized controlled trial is warranted.     

Novel antimicrobial peptides isolated from the skin secretions of Hainan odorous frog, Odorrana hainanensis

Intraperitoneal (i.p.) administration of the synthetic agonist of the glucagon like peptide-1 (GLP-1) receptor exenatide reduces food intake. Here, we evaluated possible peripheral pathways for this reduction. Exenatide (0.5 μg/kg, i.p.) was given to three, overnight food-deprived, groups of rats: total subdiaphragmatic vagotomy (VGX, severs the vagus nerve), celiaco-mesenteric ganglionectomy (CMGX, severs the splanchnic nerve) and combined VGX/CMGX. Following the injection, meal sizes (MSs) and intermeal intervals (IMIs) were determined for a total of 120 min. We found that exenatide reduced the sizes of the first two meals but failed to prolong the IMI between them, that VGX attenuated the reduction of the first MS, and that VGX, CMGX and combined VGX/CMGX attenuated the reduction of the second MS by exenatide. Therefore, the vagus nerve appears necessary for the reduction of the first MS by exenatide, whereas both nerves appear necessary for the reduction of the second MS by this peptide.     

Vagal nerve activity predicts overall survival in metastatic pancreatic cancer,mediated by inflammation

Recent research findings suggest neuro-modulation of tumors. Finding new modifiable prognostic factors paves the way for additional treatments, which is crucial in advanced cancer, particularly pancreatic cancer. This study examined the relationship between vagal nerve activity, indexed by heart rate variability (HRV), and overall survival (OS) in patients (N = 272) with advanced pancreatic cancer. A “historical prospective” design was employed, where vagal activity and other confounders were retroactively obtained from medical charts at diagnosis, and subsequent OS was examined. HRV was obtained from 10 sec ECGs near diagnosis. Levels of C-reactive protein (CRP) were measured as an inflammatory marker. OS and survival date were obtained from medical charts and the Belgian national registry. Patients with high HRV (>20 msec) survived on average more than double the days (133.5) than those with low HRV (64.0). In a multivariate cox regression, higher initial HRV was significantly correlated with lower risk of death, independent of confounders including age and cancer treatments. This relationship was statistically mediated (accounted for) by CRP levels. Importantly, in patients who lived up to one month from diagnosis only, HRV was unrelated to CRP, while in patients surviving longer, HRV was significantly inversely related to CRP (r = −0.20, p < 0.05). These results are in line with possible vagal nerve protection in a fatal cancer, and propose that the mechanism may involve neuroimmuno-modulation. Future studies must test whether vagal nerve activation may help patients with advanced cancers.     

Expression of NADPH-diaphorase in nucleus tractus solitarius after peripheral injection of E. coli endotoxin in rats

1. The possibility that peripheral exogenous pyrogens can activate brainstem nuclei by abdominal viscera afferents was studied using the NADPH-diaphorase method in E. coli lipopolysaccharide treated rats with and without ibuprofen pre-treatment.

2. NADPH-d staining revealed: (i) a significant increase in the number of NADPH-d labeled neurons in the subpostremal area of the nucleus tractus solitarius lipopolysaccharide treated rats compared with control animals (p<0.05), and (ii) an almost similar number of NADPH-d positive neurons in both control and ibuprofen pre-treated rats (p=0.091).

3. These data indicate that peripheral administration of an exogenous pyrogen stimulates the synthesis of nitric oxide in the nucleus tractus solitarius, and are consistent with the hypothesis of a direct neural link between the periphery and the hypothalamus.