Objective: To study the influence of intra cerebroventricular injection of cholecystokinin octapeptide (CCK 8) on the effect of electroacupuncture (EA) i n antagonizing the electrical activity of pain related neurons ...Objective: To study the influence of intra cerebroventricular injection of cholecystokinin octapeptide (CCK 8) on the effect of electroacupuncture (EA) i n antagonizing the electrical activity of pain related neurons in caudate nucle us (Cd) and raising pain threshold.Methods: 30 male Wistar rats were used. Operations were performed under general anesthesia with 20% urethane (1.0 g/kg of body weight). The radiant heat irradiation (nociceptive stimulus) induce d rat tail flick reaction was used as the pain index. Extracellular discharges o f pain related neurons pain excitatory neurons (PEN) and pain inhibitory ne urons (PIN) in Cd and tail flick latency (TFL) before and after cerebroventri cular microinjection of CCK 8 (15 ng) were recorded. Electroacupuncture (EA) wa s applied to bilateral "Zusanli" (ST 36).Results: ① The radiant heat focused on the tail of rats caused increase of the pain evoked discharging frequency and shortening of the evoked discharging latency of PEN or reduction of the pain evoked discharging frequency and prolongation of the inhibitory du ration of the evoked discharges of PIN and generated tail flick reflex simultaneously. ② EA of bilateral "Zusanli" (ST 36) for 15 min resulted in inh ibition of the electric activity of PEN as well as potentiation of the electrica l activity of PIN and a prolongation of tail flick latency (TFL), i.e. exhibitin g the analgesic effect of EA. The effects peaked immediately after EA, the net i ncrease value (NIV) of the pain evoked discharges of 19 PENs was reduced from 1 6.17±2.30 Hz to 5.45±2.96 Hz and TFL was prolonged from 5.03±0.31 sec to 8.89 ±0.58 sec simultaneously, the inhibitory duration of the pain evoked discharge s of 12 PINs was shortened from 5.19±0.24 sec to 2.52±0.33 sec and TFL was pro longed from 4.57±0.23 sec to 8.12±0.29 sec simultaneously. These changes recov ered gradually 10 min after EA. ③ The inhibitory effect of EA on the pain evok ed discharges of PEN and the potentiated effect of EA on the electric activities of PIN, and the prolonged effect of EA on TFL were antagonized by intra cerebr oventricular injection of 15 ng CCK 8, i.e. CCK 8 could antagonize the analges ic effect of EA. About 4 min after injection of CCK 8, the effects were most ap parent. Very soon after EA, the NIV of 13 PENs was reduced from 9.36±2.10 Hz to 2.34±0.46 Hz and TFL was prolonged from 5. 38±0.18 sec to 8.60±0.49 sec simu ltaneously, the inhibitory duration of 10 PINs was shortened from 5.54±0.32 sec to 2.09±0.79 sec and TFL was prolonged from 4.92±0.17 sec to 9.44±0.21 sec s imultaneously. About 4 min after injection of CCK 8, the NIV of PENs was recov ered to 7.44± 1.38 Hz and TFL to 5.53±0.19 sec, the inhibitory duration of PINs was recovered to 6.20± 0.61 sec and TFL to 4.54±0.16 sec. About 14 min after injection of CCK 8, it gradually recovered. Conclusion: T he results demonstrate that the antagonism of CCK 8 on analgesic effect of EA s hows a coordinated and consistent action at the levels of electrical activity of central neurons and the whole behavior reaction.展开更多
The fluidity of fresh cemented tailings backfill（CTB） slurry depends on its rheological properties. Hence, it is crucial to understand the rheology of fresh CTB slurry, which is related to the cement hydration progr...The fluidity of fresh cemented tailings backfill（CTB） slurry depends on its rheological properties. Hence, it is crucial to understand the rheology of fresh CTB slurry, which is related to the cement hydration progress and temperature evolution within CTB mixtures. For this reason, a numerical model was developed to predict the evolution of the rheological properties of fresh CTB slurry under the coupled effect of cement hydration and temperature. Experiments were conducted to investigate the rheological behaviours of the fresh CTB slurry. By comparing the simulated results with the experimental ones, the availability of this developed model was validated. Thereafter, the model was used to demonstrate the coupled effect of cement hydration and temperature on the evolution of fresh CTB slurry＇s rheological properties, under various conditions（initial CTB temperature, cement to tailings ratio, and water to cement ratio）. The obtained results are helpful to better understanding the rheology of CTB slurry.展开更多
Objective To investigate the effect of nitric oxide （NO） on the expression of apelin receptor mRNA, as well as their correlation, in the caudate nucleus of rat. Methods L-Arginine （L-Arg）, N^G-nitro-L-arginine met...Objective To investigate the effect of nitric oxide （NO） on the expression of apelin receptor mRNA, as well as their correlation, in the caudate nucleus of rat. Methods L-Arginine （L-Arg）, N^G-nitro-L-arginine methyl ester （L-NAME） and normal saline （NS） was separately microinjected into rat caudate nucleus. Expressions of neuronal NO synthase （nNOS） mRNA and apelin receptor mRNA were detected by RT-PCR at 4, 8, 12, 24 and 48 h after microinjection, and their correlation was determined. Results The expressions of nNOS mRNA and apelin receptor mRNA were both significantly increased after microinjection of L-Arg, but significantly decreased after microinjection of L-NAME compared with the NS control group. The nNOS mRNA had a positive correlation with the expression of apelin receptor mRNA after microinjection of L-Arg and L-NAME. Conclusion The activity of NOS in the central nervous system, especially in the caudate nucleus, is one of the key factors for NO to exert many kinds of biological actions, such as modulation of central pain, as a neurotransmitter. The neurobiological action of NO in rat caudate nucleus may be associated with apelin receptors.展开更多
Rattlesnakes use chemical stimuli in ambush site selection and for relocation of envenomated prey through atrike-induced chemosensory searching. Shifts in responsiveness to prey chemicals have been documented in many ...Rattlesnakes use chemical stimuli in ambush site selection and for relocation of envenomated prey through atrike-induced chemosensory searching. Shifts in responsiveness to prey chemicals have been documented in many snakes, and often correlate with prey commonly taken as snakes increase in age and size as well as geographical locations of the species. For instance, neonate rattlesnakes that prey primarily on ectotherms responded most strongly to chemical cues of commonly taken lizard prey, whereas adult rattlesnakes that prey primarily on small mammals responded significantly to chemical cues of com- monly taken rodents. In the current study, 11 Prairie Rattlesnakes Crotalus viridis viridis which were classified as large neonates based on measures of snout-vent length （SVL） and body mass, yet chronologically were at or near adulthood, were tested for their responsiveness to chemical extracts of natural and non-natural prey items. Although the snakes had eaten only neonate lab mice （Mus musculus）, they responded significantly more to chemical cues of natural prey items and particularly to chemical cues of prey normally taken by subadults （Peromyscus mice and Sceloporus lizard）. These results suggest that ontogenetic shifts in re- sponsiveness to natural prey chemical cues are innately programmed and are not based on body size or feeding experience in C. v. viridis. This does not imply, however, that growth and experience are without effects, especially with novel prey or rare prey that have experienced recent population expansion [Current Zoology 59 （2）： 175-179, 2013].展开更多
文摘Objective: To study the influence of intra cerebroventricular injection of cholecystokinin octapeptide (CCK 8) on the effect of electroacupuncture (EA) i n antagonizing the electrical activity of pain related neurons in caudate nucle us (Cd) and raising pain threshold.Methods: 30 male Wistar rats were used. Operations were performed under general anesthesia with 20% urethane (1.0 g/kg of body weight). The radiant heat irradiation (nociceptive stimulus) induce d rat tail flick reaction was used as the pain index. Extracellular discharges o f pain related neurons pain excitatory neurons (PEN) and pain inhibitory ne urons (PIN) in Cd and tail flick latency (TFL) before and after cerebroventri cular microinjection of CCK 8 (15 ng) were recorded. Electroacupuncture (EA) wa s applied to bilateral "Zusanli" (ST 36).Results: ① The radiant heat focused on the tail of rats caused increase of the pain evoked discharging frequency and shortening of the evoked discharging latency of PEN or reduction of the pain evoked discharging frequency and prolongation of the inhibitory du ration of the evoked discharges of PIN and generated tail flick reflex simultaneously. ② EA of bilateral "Zusanli" (ST 36) for 15 min resulted in inh ibition of the electric activity of PEN as well as potentiation of the electrica l activity of PIN and a prolongation of tail flick latency (TFL), i.e. exhibitin g the analgesic effect of EA. The effects peaked immediately after EA, the net i ncrease value (NIV) of the pain evoked discharges of 19 PENs was reduced from 1 6.17±2.30 Hz to 5.45±2.96 Hz and TFL was prolonged from 5.03±0.31 sec to 8.89 ±0.58 sec simultaneously, the inhibitory duration of the pain evoked discharge s of 12 PINs was shortened from 5.19±0.24 sec to 2.52±0.33 sec and TFL was pro longed from 4.57±0.23 sec to 8.12±0.29 sec simultaneously. These changes recov ered gradually 10 min after EA. ③ The inhibitory effect of EA on the pain evok ed discharges of PEN and the potentiated effect of EA on the electric activities of PIN, and the prolonged effect of EA on TFL were antagonized by intra cerebr oventricular injection of 15 ng CCK 8, i.e. CCK 8 could antagonize the analges ic effect of EA. About 4 min after injection of CCK 8, the effects were most ap parent. Very soon after EA, the NIV of 13 PENs was reduced from 9.36±2.10 Hz to 2.34±0.46 Hz and TFL was prolonged from 5. 38±0.18 sec to 8.60±0.49 sec simu ltaneously, the inhibitory duration of 10 PINs was shortened from 5.54±0.32 sec to 2.09±0.79 sec and TFL was prolonged from 4.92±0.17 sec to 9.44±0.21 sec s imultaneously. About 4 min after injection of CCK 8, the NIV of PENs was recov ered to 7.44± 1.38 Hz and TFL to 5.53±0.19 sec, the inhibitory duration of PINs was recovered to 6.20± 0.61 sec and TFL to 4.54±0.16 sec. About 14 min after injection of CCK 8, it gradually recovered. Conclusion: T he results demonstrate that the antagonism of CCK 8 on analgesic effect of EA s hows a coordinated and consistent action at the levels of electrical activity of central neurons and the whole behavior reaction.
基金Project(SKLCRSM13KFB05)supported by State Key Laboratory of Coal Resources and Safe Mining,China University of Mining and Technology(Beijing)
文摘The fluidity of fresh cemented tailings backfill（CTB） slurry depends on its rheological properties. Hence, it is crucial to understand the rheology of fresh CTB slurry, which is related to the cement hydration progress and temperature evolution within CTB mixtures. For this reason, a numerical model was developed to predict the evolution of the rheological properties of fresh CTB slurry under the coupled effect of cement hydration and temperature. Experiments were conducted to investigate the rheological behaviours of the fresh CTB slurry. By comparing the simulated results with the experimental ones, the availability of this developed model was validated. Thereafter, the model was used to demonstrate the coupled effect of cement hydration and temperature on the evolution of fresh CTB slurry＇s rheological properties, under various conditions（initial CTB temperature, cement to tailings ratio, and water to cement ratio）. The obtained results are helpful to better understanding the rheology of CTB slurry.
文摘Objective To investigate the effect of nitric oxide （NO） on the expression of apelin receptor mRNA, as well as their correlation, in the caudate nucleus of rat. Methods L-Arginine （L-Arg）, N^G-nitro-L-arginine methyl ester （L-NAME） and normal saline （NS） was separately microinjected into rat caudate nucleus. Expressions of neuronal NO synthase （nNOS） mRNA and apelin receptor mRNA were detected by RT-PCR at 4, 8, 12, 24 and 48 h after microinjection, and their correlation was determined. Results The expressions of nNOS mRNA and apelin receptor mRNA were both significantly increased after microinjection of L-Arg, but significantly decreased after microinjection of L-NAME compared with the NS control group. The nNOS mRNA had a positive correlation with the expression of apelin receptor mRNA after microinjection of L-Arg and L-NAME. Conclusion The activity of NOS in the central nervous system, especially in the caudate nucleus, is one of the key factors for NO to exert many kinds of biological actions, such as modulation of central pain, as a neurotransmitter. The neurobiological action of NO in rat caudate nucleus may be associated with apelin receptors.
文摘Rattlesnakes use chemical stimuli in ambush site selection and for relocation of envenomated prey through atrike-induced chemosensory searching. Shifts in responsiveness to prey chemicals have been documented in many snakes, and often correlate with prey commonly taken as snakes increase in age and size as well as geographical locations of the species. For instance, neonate rattlesnakes that prey primarily on ectotherms responded most strongly to chemical cues of commonly taken lizard prey, whereas adult rattlesnakes that prey primarily on small mammals responded significantly to chemical cues of com- monly taken rodents. In the current study, 11 Prairie Rattlesnakes Crotalus viridis viridis which were classified as large neonates based on measures of snout-vent length （SVL） and body mass, yet chronologically were at or near adulthood, were tested for their responsiveness to chemical extracts of natural and non-natural prey items. Although the snakes had eaten only neonate lab mice （Mus musculus）, they responded significantly more to chemical cues of natural prey items and particularly to chemical cues of prey normally taken by subadults （Peromyscus mice and Sceloporus lizard）. These results suggest that ontogenetic shifts in re- sponsiveness to natural prey chemical cues are innately programmed and are not based on body size or feeding experience in C. v. viridis. This does not imply, however, that growth and experience are without effects, especially with novel prey or rare prey that have experienced recent population expansion [Current Zoology 59 （2）： 175-179, 2013].
