Cholecystokinin octapeptide (CCK-8) has been shown to be a neuropeptide with potent anti-opioid activity. Previous studies have shown that central administration of nanogram dose of CCK-8 totally abolished morphine an...Cholecystokinin octapeptide (CCK-8) has been shown to be a neuropeptide with potent anti-opioid activity. Previous studies have shown that central administration of nanogram dose of CCK-8 totally abolished morphine analgesia in the rat, an effect mediated by CCK-B receptor in central nervous system. In the present study CCK-B antagonist L-365,260 was injected intracerebroventricularly (icv) to Wistar rats to see its effect on the analgesic effect induced by electroacupuncture (EA) stimulation. A marked potentiation of EA-induced analgesia was observed. The degree of potentiation depends on the frequency of EA used, with a rank order of 100 Hz > 15 Hz = 2/15 Hz>> 2Hz. In a strain of rat with acoustically evoked epileptic seizure (P77PMC rats), an extra-ordinarily strong analgesic effect was produced in response to 100 Hz EA stimulation, which was similar to that in Wistar rats pre-treat ed with L-365,260. However, L-365,260 was not effective in potentiating EA analgesia in P77PMC rats. The results suggest that (1) high frequency EA is more likely to increase the release of CCK-8 in CNS as compared to low frequency EA, and (2) P77PMC rats may have a functional defect of the central CCK neurons in the nature of either a low CCK content or a reduced rate of release of CCK-8 in the CNS.展开更多
Growing evidence has been found to suggest that early development of the central auditory system is dependent on acoustic stimuli. Peripheral damage caused by noise exposure and ototoxic drugs can induce functional an...Growing evidence has been found to suggest that early development of the central auditory system is dependent on acoustic stimuli. Peripheral damage caused by noise exposure and ototoxic drugs can induce functional and anatomical changes along the auditory pathways. The inferior colliculus (IC) is a unique structure in the auditory system located between the primary auditory nuclei of the brainstem and the thala-mus. Damage to the IC inhibitory circuitry may affect central auditory processing and sound perception. Here, we review some of the striking electrophysiological changes in the IC that occur after noise exposure and ototoxic drug treatment. A common occurrence that emerges in the IC after peripheral damage is hyper-excitability of sound-evoked response. The hyperexcitability of the IC is likely related with reduced inhibi-tory response that requires normal peripheral inputs. Early age hearing loss can result in a long lasting in-creased susceptibility to audiogenic seizure which is related to hyperactivity in the IC evoked by loud sounds. Our studies suggest that hearing loss can cause increased IC neuron responsiveness which may be related to tinnitus, hyperacusis, and audiogenic seizure.展开更多
The main objective of the study was to determine the effect of gestation and postgestation periods on development and course of seizure activity. The data obtained in the study showed that i) there is a reduction of b...The main objective of the study was to determine the effect of gestation and postgestation periods on development and course of seizure activity. The data obtained in the study showed that i) there is a reduction of both EEG and behavioral seizures during gestation in the presence of hippocampal epileptogenic locus (kindling model);ii) suppression of audiogenic seizures occurs in gestation, and development of audiogenic kindling and decrease of seizure reactions occur in the pseudogestation state. It is assumed that in gestation period the intensification of the possible endogenous inhibitory mechanisms follows the course of seizure activity.展开更多
基金This study was supported by the National Natural Science Foundation of China, and a grant from the National Institute of Drua Abuse, USA (DA 03983).
文摘Cholecystokinin octapeptide (CCK-8) has been shown to be a neuropeptide with potent anti-opioid activity. Previous studies have shown that central administration of nanogram dose of CCK-8 totally abolished morphine analgesia in the rat, an effect mediated by CCK-B receptor in central nervous system. In the present study CCK-B antagonist L-365,260 was injected intracerebroventricularly (icv) to Wistar rats to see its effect on the analgesic effect induced by electroacupuncture (EA) stimulation. A marked potentiation of EA-induced analgesia was observed. The degree of potentiation depends on the frequency of EA used, with a rank order of 100 Hz > 15 Hz = 2/15 Hz>> 2Hz. In a strain of rat with acoustically evoked epileptic seizure (P77PMC rats), an extra-ordinarily strong analgesic effect was produced in response to 100 Hz EA stimulation, which was similar to that in Wistar rats pre-treat ed with L-365,260. However, L-365,260 was not effective in potentiating EA analgesia in P77PMC rats. The results suggest that (1) high frequency EA is more likely to increase the release of CCK-8 in CNS as compared to low frequency EA, and (2) P77PMC rats may have a functional defect of the central CCK neurons in the nature of either a low CCK content or a reduced rate of release of CCK-8 in the CNS.
基金supported by Royal National Institute for Deaf People
文摘Growing evidence has been found to suggest that early development of the central auditory system is dependent on acoustic stimuli. Peripheral damage caused by noise exposure and ototoxic drugs can induce functional and anatomical changes along the auditory pathways. The inferior colliculus (IC) is a unique structure in the auditory system located between the primary auditory nuclei of the brainstem and the thala-mus. Damage to the IC inhibitory circuitry may affect central auditory processing and sound perception. Here, we review some of the striking electrophysiological changes in the IC that occur after noise exposure and ototoxic drug treatment. A common occurrence that emerges in the IC after peripheral damage is hyper-excitability of sound-evoked response. The hyperexcitability of the IC is likely related with reduced inhibi-tory response that requires normal peripheral inputs. Early age hearing loss can result in a long lasting in-creased susceptibility to audiogenic seizure which is related to hyperactivity in the IC evoked by loud sounds. Our studies suggest that hearing loss can cause increased IC neuron responsiveness which may be related to tinnitus, hyperacusis, and audiogenic seizure.
文摘The main objective of the study was to determine the effect of gestation and postgestation periods on development and course of seizure activity. The data obtained in the study showed that i) there is a reduction of both EEG and behavioral seizures during gestation in the presence of hippocampal epileptogenic locus (kindling model);ii) suppression of audiogenic seizures occurs in gestation, and development of audiogenic kindling and decrease of seizure reactions occur in the pseudogestation state. It is assumed that in gestation period the intensification of the possible endogenous inhibitory mechanisms follows the course of seizure activity.
