Extracellular discharges of neurons in the dorsomedial nucleus（DMN）were recordedwith glass microelectrode from rat hypothalamic slices.The firing frequency decreased in 77 andincreased in 48 units during the additio...Extracellular discharges of neurons in the dorsomedial nucleus（DMN）were recordedwith glass microelectrode from rat hypothalamic slices.The firing frequency decreased in 77 andincreased in 48 units during the addition of norepinephrine into the bath(NE,2×10<sup>-5</sup> mol/L)of160 units when the slices were perfused with artificial cerebrospinal fluid （ACSF）.Most of theseresponses could be antagonized by Yohimbine(YOH,2×10<sup>-5</sup>～4×10<sup>-5</sup> mol/L).Nevertheless,when the perfusion fluid was changed,i.e.,with low Ca<sup>2+</sup>-high Mg<sup>2+</sup> ACSF（CM-ACSF）whichcould block the chemical synaptic transmission,26 out of 35 units were inhibited by NE and only1 unit excited.The inhibition could he blocked by YOH. A very significant difference（P【0.01）was seen between the data obtained in ACSF and those in CM-ACSF.Furthermore,all NE-inhibited units in ACSF were also NE-inhibited in CM-ACSF,but the majority of NE-excited u-nits in ACSF changed into NE-inhibited or NE-unresponsive in CM-ACSF.The results suggestedthat NE produced a direct inhibitory effect on neurons in DMN which was mediated by the post-synaptic alpha 2 adrenergic receptors.展开更多
The unit discharges in the dorsomedial nucleus of the hypothalamus (DMH) were extracellularly recorded with microelectrodes in trauma models of male Sprague-Dawley rats. The main results were as follows : (1) The tota...The unit discharges in the dorsomedial nucleus of the hypothalamus (DMH) were extracellularly recorded with microelectrodes in trauma models of male Sprague-Dawley rats. The main results were as follows : (1) The total number of spontaneously discharged units in DMH of trauma rats was markedly decreased while the number of pain-sensitive units (nociceptive neurons) did not change obviously. (2) The electroacupuncture (EA)at Zusanli (ST36) and Sanyinjiao (Sp6) decreased the spontaneous and pain-evoked firing (discharge) rate, and shortened the durations of pain-evoked firing of pain-excited units in DMH. It also resulted in increase in spontaneous discharge rate of pain-inhibited units and relief of their inhibition from the peripheral noxious stimulations. These results suggest that the depression of the function of DMH caused by the persistent peripheral noxious stimulation may be one of the mechanisms of hyperalgesia. EA at the points of Zusanli (ST36) and Sanyinjiao (Sp6) can interfere with the conduction of pain signals to DMH in the central nervous system and thereby prevent DMH from being depressed , which may partly account for the central mechanisms of acupuncture-analgesia in chronic pain state.展开更多
文摘Extracellular discharges of neurons in the dorsomedial nucleus（DMN）were recordedwith glass microelectrode from rat hypothalamic slices.The firing frequency decreased in 77 andincreased in 48 units during the addition of norepinephrine into the bath(NE,2×10<sup>-5</sup> mol/L)of160 units when the slices were perfused with artificial cerebrospinal fluid （ACSF）.Most of theseresponses could be antagonized by Yohimbine(YOH,2×10<sup>-5</sup>～4×10<sup>-5</sup> mol/L).Nevertheless,when the perfusion fluid was changed,i.e.,with low Ca<sup>2+</sup>-high Mg<sup>2+</sup> ACSF（CM-ACSF）whichcould block the chemical synaptic transmission,26 out of 35 units were inhibited by NE and only1 unit excited.The inhibition could he blocked by YOH. A very significant difference（P【0.01）was seen between the data obtained in ACSF and those in CM-ACSF.Furthermore,all NE-inhibited units in ACSF were also NE-inhibited in CM-ACSF,but the majority of NE-excited u-nits in ACSF changed into NE-inhibited or NE-unresponsive in CM-ACSF.The results suggestedthat NE produced a direct inhibitory effect on neurons in DMN which was mediated by the post-synaptic alpha 2 adrenergic receptors.
文摘The unit discharges in the dorsomedial nucleus of the hypothalamus (DMH) were extracellularly recorded with microelectrodes in trauma models of male Sprague-Dawley rats. The main results were as follows : (1) The total number of spontaneously discharged units in DMH of trauma rats was markedly decreased while the number of pain-sensitive units (nociceptive neurons) did not change obviously. (2) The electroacupuncture (EA)at Zusanli (ST36) and Sanyinjiao (Sp6) decreased the spontaneous and pain-evoked firing (discharge) rate, and shortened the durations of pain-evoked firing of pain-excited units in DMH. It also resulted in increase in spontaneous discharge rate of pain-inhibited units and relief of their inhibition from the peripheral noxious stimulations. These results suggest that the depression of the function of DMH caused by the persistent peripheral noxious stimulation may be one of the mechanisms of hyperalgesia. EA at the points of Zusanli (ST36) and Sanyinjiao (Sp6) can interfere with the conduction of pain signals to DMH in the central nervous system and thereby prevent DMH from being depressed , which may partly account for the central mechanisms of acupuncture-analgesia in chronic pain state.
