Ventrolateral periaqueductal gray metabotropic glutamate receptor subtypes 7 and 8 mediate opposite effects on cardiosomatic motor reflex in rats / 南方医科大学学报

<p><b>OBJECTIVE</b>To investigate the role of ventrolateral periaqueductal gray (VL-PAG) metabotropic glutamate receptors subtype 7 and 8 (mGluR 7/8) in descending modulation of cardiosomatic motor reflex (CMR) in rats.</p><p><b>METHODS</b>AMN082 (agonist of mGluR 7) and DCPG (agonist of mGluR 8) were injected into the VL-PAG of a rat model of CMR to observe their effects in modulating CMR. The raphe magnus nucleus (NRM) or the gigantocellular reticular nucleus (Gi) was then damaged, and the changes in VL-PAG descending modulation were observed.</p><p><b>RESULTS</b>Selective activation of mGluR 7 of the VL-PAG by AMN082 obviously facilitated capsaicin (CAP)-induced CMR (P<0.05), which was suppressed by DCPG-induced mGluR 8 activation (P<0.05). These facilitatory or inhibitory effects were completely reversed by group III mGluR antagonist MSOP. Damaging the NRM of VL-PAG main relay nucleus did not significantly affect the facilitatory effect produced by AMN082 microinjection (P>0.05), but partially attenuated the inhibitory effect of DCPG microinjection (P<0.05). Both the facilitatory effect of AMN082 and the inhibitory effect of DCPG were reduced obviously after bilateral Gi damage (P<0.05).</p><p><b>CONCLUSION</b>VL-PAG mGluR 7 and mGluR 8 mediate biphasic regulation of CMR in rats probably through activation of different sub-nuclei and different neurons in the rostroventral medulla.</p>

Descending inhibitory modulation of nucleus raphes magnus in cardiac nociception in rats and its pathway / 吉林大学学报(医学版)

Objective To observe the cardiosomatic motor reflex (CMR)of rats, and to clarify the descending modulation of nucleus raphes magnus (NRM)in cardiac nociception and its pathway.Methods 34 male healthy SD rats were randomly divided into NRM electrical stimulation group (n=8 ), NRM stimulation combined with dorsolateral funiculus (DLF ) transection group (n= 8 ), NRM stimulation combined with antagonist of 5-hydroxytryptamine (5-HT)methysergide intrathecal administration group (n=18).The rat model of CMR was established through inj ecting capsaicin into the pericardial sac of the rats in various groups. The electromyogram (EMG) response of dorsal spinotrapezius muscle was used as detection index, and by placing the stimulation electrode in NRM and (or)intrathecal catheterization, the descending inhibitory modulation of NRM in CMR and the influence of DLF tansection or methysergide intrathecal administration in descending inhibitory modulation of NRM were observed.Results Compared with before stimulation,the EMG response was decreased after NRM electrical stimulation (75 μA) (P 0.05 ). In addition, after intrathecal administration of methysergide,the EMG response after NRM stimulation was significantly increased compared with before intrathecal treatment of methysergide (P<0.05),but it was still significantly smaller than that of its control (P<0.05). Conclusion Cardiac nociception evoked by capsaicin stimulation is subject to descending inhibitory modulation from NRM,and the descending inhibition from NRM is conveyed via the DLF and partially mediated by endogenous 5-HT system.

Descending modulation of cardiac nociception by the rostral ventromedial medulla in rats / 南方医科大学学报

<p><b>OBJECTIVE</b>To observe the descending modulation of cardiac nociception by the rostral ventromedial medulla (RVM) in rats.</p><p><b>METHODS</b>A rat model of cardiosomatic motor reflex (CMR) was established by injecting capsaicin into the pericardial sac to induce cardiac nociception, and the electromyogram (EMG) response of the dorsal spinotrapezius muscle was studied. The RVM was electrically stimulated (25, 75 and 100 µA) or destroyed to examine whether RVM exerted descending modulation on cardiac nociception.</p><p><b>RESULTS</b>Electrical stimulation of the RVM at 8 sites produced intensity-dependent inhibition of EMG responses to noxious cardiac stimulus (F[2,21]=43.188, P=0.001). Electrical stimulation at 3 sites caused facilitated EMG responses, but the increased magnitude of the EMG was not dependent on stimulation intensity (F[2,6]=0.884, P=0.461). Stimulation at 11 sites produced biphasic effects: at a low intensity (25 µA), the elicited EMG magnitude was significantly larger than baseline (P<0.05), and at greater intensities (75/100 µA), the stimulation caused suppression of the EMG magnitude to a level significantly lower than the baseline (P<0.05). Electrolytic lesion of the RVM resulted in significantly increased EMG responses compared with the baseline and sham lesion group.</p><p><b>CONCLUSION</b>Cardiac nociception evoked by capsaicin stimulation is subjected to descending biphasic modulation by the RVM, which produces predominantly descending inhibition on heart pain.</p>

Meta-analysis of the risk factors for clinical anastomotic leakage after resection of rectal cancer in China / 西安交通大学学报(医学版)

Objective To explore the risk factors for clinical anastomotic leakage after resection of rectal cancer in China. Methods By meta-analysis we made a comprehensive analysis of the risk factors for clinical anastomotic leakage after resection of rectal cancer based on 19 articles published in China between January 1999 and January 2009. Results The anastomotic leakage rate was higher in the patients aged 60 years old and above than in those younger, with the combined odds ratio (OR) value being 0.50 (95% CI: 0.33-0.76) (P<0.01). The incidence rate was higher in the male patients than in the female ones, with the combined OR value being 2.17 (95% CI: 1.38-3.42) (P<0.01). The incidence rate in the patients with the distance of tumor from the lower margin to anal verge being 7cm and shorter was higher than that with longer distance, with the combined OR value being 1.79 (95% CI: 1.37-2.35) (P<0.01). The incidence rate in the patients who had received radiotherapy preoperatively was higher than that in those who had not, with the combined OR value of 3.66 (95% CI: 2.19-6.09) (P<0.01). The incidence rate in the patients who had received stapler anastomosis was higher than that in the patients who had received manual anastomosis, with the combined OR value being 0.70 (95% CI: 0.47-1.05), but there was no significant difference between them (P>0.05). The incidence rate was higher in the patients with diabetes mellitus than in the healthy ones, with the combined OR value being 3.16 (95% CI: 2.27-4.39) (P<0.01). The incidence rate was lower in the patients with Dukes A and B stages than in those with Dukes C and D stages, with the combined OR value being 0.61 (95% CI: 0.45-0.83) (P<0.01). The incidence rate in the patients with high malignance degree in clinicopathological types was higher than that with low malignance degree, with the combined OR value being 2.17 (95% CI: 1.38-3.42) (P<0.01). The incidence rate was lower in the patients who had received preventive colostomy than in those who had not, with the combined OR value being 0.39 (95% CI: 0.14-1.05), but there was no significant difference between them (P>0.05). The incidence rate was higher in the patients who had got selective operation than in those who had got emergency operation, with the combined OR value being 0.27 (95% CI: 0.13-0.56). Conclusion The risk factors of anastomotic leakage after resection of rectal cancer are as follows: 60 years old and above, male patients, diabetes mellitus, preoperative neo-adjuvant radiotherapy, the distance of tumor from the lower margin to the anal verge being shorter than 7cm, Dukes C and D stages, high malignance degree in clinicopathological types, and emergency operation.