Sex-dependent and -independent regulation of thyrotropin-releasing hormone expression in the hypothalamic dorsomedial nucleus by negative energy balance, exercise, and chronic stress.

The dorsomedial nucleus of the hypothalamus (DMH) is part of the brain circuits that modulate organism responses to the circadian cycle, energy balance, and psychological stress. A large group of thyrotropin-releasing hormone (Trh) neurons is localized in the DMH; they comprise about one third of the DMH neurons that project to the lateral hypothalamus area (LH). We tested their response to various paradigms. In male Wistar rats, food restriction during adulthood, or chronic variable stress (CVS) during adolescence down-regulated adult DMH Trh mRNA levels compared to those in sedentary animals fed ad libitum; two weeks of voluntary wheel running during adulthood enhanced DMH Trh mRNA levels compared to pair-fed rats. Except for their magnitude, female responses to exercise were like those in male rats; in contrast, in female rats CVS did not change DMH Trh mRNA levels. A very strong negative correlation between DMH Trh mRNA levels and serum corticosterone concentration in rats of either sex was lost in CVS rats. CVS canceled the response to food restriction, but not that to exercise in either sex. TRH receptor 1 (Trhr) cells were numerous along the rostro-caudal extent of the medial LH. In either sex, fasting during adulthood reduced DMH Trh mRNA levels, and increased LH Trhr mRNA levels, suggesting fasting may inhibit the activity of TRHDMH->LH neurons. Thus, in Wistar rats DMH Trh mRNA levels are regulated by negative energy balance, exercise and chronic variable stress through sex-dependent and -independent pathways.

[Effect of electroacupuncture preconditioning on neuronal activities in lateral hypothalamus area of myocardial ischemia reperfusion injury rats].

OBJECTIVE: To observe the effect of electroacupuncture (EA) preconditioning of "Shenmen" (HT7)-"Tongli" (HT5) segment of the Heart Meridian on neuronal electrical activities of lateral hypothalamus area (LHA) in rats with myocardial ischemia reperfusion injury (MIRI), so as to investigate its possible mechanism underlying improvement of MIRI. METHODS: Twenty-four SD rats were randomly divided into sham, model, EA and damage + EA (D+EA) groups, with 6 rats in each group. The MIRI model was established by occlusion of the anterior descending branch (ADB) of the left coronary artery for 30 min, followed by reperfusion for 2 h. In the sham operation group, the ADB was only threaded beneath the artery without ligation. EA (2 Hz, 1 V) was applied to bilateral HT7-HT5 for 20 min, once daily for 7 days. In the D+EA group, FN was injected with 0.4 µL of 1 g/L kainic acid solution. Electrocardiogram (ECG) of the neck-thoracic lead was recorded by using PowerLab. The electrical activities of the LHA region were recorded by the implanted microelectrode array (2×4) and Plexon multi-channel acquisition system. Cluster analysis of neuronal signals was carried out by Offline Sorter software. The discharge waveforms, autocorrelation and cross-correlation of neuronal activities were analyzed by using Neuro Explorer software. RESULTS: Compared with the sham group, the ECG-ST height was significantly increased (P<0.05), the discharge frequency of pyramidal neurons was significantly reduced (P<0.01), while the discharge frequency of interneurons was increased (P<0.01) in the model group. After EA treatment, the ECG-ST height was significantly decreased (P<0.05), the discharge frequency of pyramidal neurons was significantly increased (P<0.01) relevant to the model group. In comparison with the EA group, the ECG-ST height in the D+EA group was significantly elevated (P<0.05), whereas the discharge frequency of pyramidal neurons was significantly decreased (P<0.01). The discharge frequency of interneurons was kept increasing after MIRI. Real-time spectrum analysis showed that the local field potential spectrum energy of the EA group was significantly lower than that of the model group and the D+EA group. CONCLUSION: EA preconditioning of Heart Meridian can significantly increase the discharge frequency of LHA excitatory pyramidal neurons and reduce the energy of the local field potential spectrum, which maybe one of the important mechanisms of EA in anti -MIRI.

[Effect of electroacupuncture preconditioning on the contents of dopamine and 5-hydroxytryptamine in lateral hypothalamus area and cerebellar fastigial nucleus of rats with myocardial ischemia-reperfusion injury].

OBJECTIVE: To observe the effect of electroacupuncture (EA) preconditioning at heart meridian acupoints on the contents of dopamine (DA) and 5-hydroxytryptamine (5-HT) in lateral hypothalamus area (LHA) and cerebellar fastigial nucleus (FN) in the rats with acute myocardial ischemia-reperfusion injury (MIRI), and explore the role and mechanism of LHA and FN in the effect of EA at heart meridian acupoints against acute MIRI. METHODS: Sixty SD rats were randomly divided into a sham-operation group, a model group, an EA heart meridian group and an EA lung meridian group, 12 rats in each group, as well as an LHA plus heart meridian group (damage of bilateral LHA) and an FN plus heart meridian group (damage of bilateral FN), 6 rats in each one. Three days after nucleus destruction, EA was applied to "Shenmen" (HT 7) and "Tongli" (HT 5) in the EA heart meridian group, the LHA plus heart meridian group and the FN plus heart meridian group and EA was applied to "Taiyuan" (LU 9) and "Lieque" (LU 7) in the EA lung meridian group, with 1 V in stimulating voltage and 2 Hz in frequency, lasting 20 minutes each time, once a day, for consecutively 7 days before model replication. Except in the sham-operation group, MIRI rat models were duplicated by ligation of the left anterior descending branch of the coronary artery in the rest groups. Using Power lab physiological recorder, ST segment displacement value was recorded before modeling, 30 min after ligation and 120 min after reperfusion separately. The high performance liquid chromatography-electrochemical detection and analysis system was adopted to determine the contents of DA and 5-HT in LHA and FN dialysate after rat modeling in each group. RESULTS: In comparison of ST segment displacement value 30 min after ligation and 120 min after reperfusion among groups, the value in the model group was higher than that in the sham-operation group (P<0.01), those in the EA heart meridian group, the LHA plus heart meridian group, the FN plus heart meridian group and the EA lung meridian group were lower than those in the model group successively (P<0.01) and those in the EA heart meridian group were lower than those in the EA lung meridian group, the LHA plus heart meridian group and the FN plus heart meridian group successively (P<0.01). The contents of DA and 5-HT in FN and LHA in the model group were lower than those in the sham-operation group (P<0.01). Except in the groups with nucleus lesions, the contents of DA and 5-HT in FN and LHA of each intervention group were higher than those in the model group (P<0.01), the contents of DA and 5-HT in FN in the EA heart meridian group were higher than those in the EA lung meridian group and the LHA plus heart meridian group (P<0.01) and the content of 5-HT in LHA was higher than those in the EA lung meridian group and the FN plus heart meridian group (P<0.01) separately, the content of DA in LHA was higher than that in the EA lung meridian group (P<0.01). CONCLUSION: EA preconditioning at heart meridian acupoints can effectively alleviate myocardial injury in acute MIRI rats, during which, DA and 5-HT in LHA and FN may be the important material basis.

Effect of electroacupuncture preconditioning on the contents of dopamine and 5-hydroxytryptamine in lateral hypothalamus area and cerebellar fastigial nucleus of rats with myocardial ischemia-reperfusion injury / 中国针灸

OBJECTIVE@#To observe the effect of electroacupuncture (EA) preconditioning at heart meridian acupoints on the contents of dopamine (DA) and 5-hydroxytryptamine (5-HT) in lateral hypothalamus area (LHA) and cerebellar fastigial nucleus (FN) in the rats with acute myocardial ischemia-reperfusion injury (MIRI), and explore the role and mechanism of LHA and FN in the effect of EA at heart meridian acupoints against acute MIRI.@*METHODS@#Sixty SD rats were randomly divided into a sham-operation group, a model group, an EA heart meridian group and an EA lung meridian group, 12 rats in each group, as well as an LHA plus heart meridian group (damage of bilateral LHA) and an FN plus heart meridian group (damage of bilateral FN), 6 rats in each one. Three days after nucleus destruction, EA was applied to "Shenmen" (HT 7) and "Tongli" (HT 5) in the EA heart meridian group, the LHA plus heart meridian group and the FN plus heart meridian group and EA was applied to "Taiyuan" (LU 9) and "Lieque" (LU 7) in the EA lung meridian group, with 1 V in stimulating voltage and 2 Hz in frequency, lasting 20 minutes each time, once a day, for consecutively 7 days before model replication. Except in the sham-operation group, MIRI rat models were duplicated by ligation of the left anterior descending branch of the coronary artery in the rest groups. Using Power lab physiological recorder, ST segment displacement value was recorded before modeling, 30 min after ligation and 120 min after reperfusion separately. The high performance liquid chromatography-electrochemical detection and analysis system was adopted to determine the contents of DA and 5-HT in LHA and FN dialysate after rat modeling in each group.@*RESULTS@#In comparison of ST segment displacement value 30 min after ligation and 120 min after reperfusion among groups, the value in the model group was higher than that in the sham-operation group (@*CONCLUSION@#EA preconditioning at heart meridian acupoints can effectively alleviate myocardial injury in acute MIRI rats, during which, DA and 5-HT in LHA and FN may be the important material basis.

[Effects of acupuncture at "Zusanli" (ST 36) on sensitive neurons of gastric distention in LHA-FN circuit in rats].

OBJECTIVE: To observe the regulation effects of acupuncture at "Zusanli" (ST 36) on sensitive neurons of gastric distention (GD) in lateral hypothalamus area (LHA) and fastigial nuclear (FN) circuit, and to explore the central mechanism of acupuncture for gastric function. METHODS: A total of 101 rats were randomly assigned into a LHA group (50 rats) and a FN group (51 rats). Gastric distension surgery was performed in all the rats. According to the stereotaxic atlas of rat brain, the LHA and FN were located, followed by craniotomy. The endocranium was removed to exposure brain tissue, and warm paraffin oil was used to prevent desiccation. The electrical activities of neurons were probed by glass microelectrode to perform extracellular recording. The electrical activities of GD sensitive neurons in LHA were observed in LHA group, while those in FN were observed in FN group. One min after the electrical signal of neurons was recorded, acupuncture was given at left "Zusanli" (ST 36) with mild reinforcing and attenuating technique, 120~180 times/min for 1 min. The effects of acupuncture at "Zusanli" (ST 36) on spontaneous discharge of GD sensitive neurons in LHA and FN were observed. RESULTS: (1) Totally 54 LHA neurons of spontaneous discharge in LHA group and 85 FN neurons in FN group were recorded. GD-excitatory (GD-E) neurons were mainly in the LHA group (46.3%) and GD-non-response (GD-N) neurons were mainly in the FN group (54.12%). The average discharge frequency of GD-N neurons was (39.03±14.91) spikes/s, that of GD-E neurons was (19.67±12.08) spikes/s, and that of GD-inhibitory (GD-I) neurons was (28.76±7.26) spikes/s, which were statistically different from those before GD (all P<0.01). (2) In LHA group, acupuncture excited the activity of GD-E neurons, and inhibited the activity of GD-I neurons (P<0.05); in FN group, acupuncture excited the activity of GD-I neurons, but showed no effect on GD-E neurons (P<0.01). CONCLUSIONS: The signal of GD and acupuncture could converge in LHA and FN; acupuncture presented different regulation effects on identical type of GD-sensitive neurons in different nuclear groups; LHA-FN circuit might participate in central integration mechanism of acupuncture on gastric function.

Effects of acupuncture at "Zusanli" (ST 36) on sensitive neurons of gastric distention in LHA-FN circuit in rats / 中国针灸

<p><b>OBJECTIVE</b>To observe the regulation effects of acupuncture at "Zusanli" (ST 36) on sensitive neurons of gastric distention (GD) in lateral hypothalamus area (LHA) and fastigial nuclear (FN) circuit, and to explore the central mechanism of acupuncture for gastric function.</p><p><b>METHODS</b>A total of 101 rats were randomly assigned into a LHA group (50 rats) and a FN group (51 rats). Gastric distension surgery was performed in all the rats. According to the stereotaxic atlas of rat brain, the LHA and FN were located, followed by craniotomy. The endocranium was removed to exposure brain tissue, and warm paraffin oil was used to prevent desiccation. The electrical activities of neurons were probed by glass microelectrode to perform extracellular recording. The electrical activities of GD sensitive neurons in LHA were observed in LHA group, while those in FN were observed in FN group. One min after the electrical signal of neurons was recorded, acupuncture was given at left "Zusanli" (ST 36) with mild reinforcing and attenuating technique, 120~180 times/min for 1 min. The effects of acupuncture at "Zusanli" (ST 36) on spontaneous discharge of GD sensitive neurons in LHA and FN were observed.</p><p><b>RESULTS</b>(1) Totally 54 LHA neurons of spontaneous discharge in LHA group and 85 FN neurons in FN group were recorded. GD-excitatory (GD-E) neurons were mainly in the LHA group (46.3%) and GD-non-response (GD-N) neurons were mainly in the FN group (54.12%). The average discharge frequency of GD-N neurons was (39.03±14.91) spikes/s, that of GD-E neurons was (19.67±12.08) spikes/s, and that of GD-inhibitory (GD-I) neurons was (28.76±7.26) spikes/s, which were statistically different from those before GD (all<0.01). (2) In LHA group, acupuncture excited the activity of GD-E neurons, and inhibited the activity of GD-I neurons (<0.05); in FN group, acupuncture excited the activity of GD-I neurons, but showed no effect on GD-E neurons (<0.01).</p><p><b>CONCLUSIONS</b>The signal of GD and acupuncture could converge in LHA and FN; acupuncture presented different regulation effects on identical type of GD-sensitive neurons in different nuclear groups; LHA-FN circuit might participate in central integration mechanism of acupuncture on gastric function.</p>