摘要:

THE induction of oxytocin receptor (OTR) synthesis in the periphery and in the brain by estrogen is critical for reproductive success. Oxytocin receptors are involved in the control of parturition, milk ejection, and sexual and maternal behaviors. The discovery of a second estrogen receptor (ERβ) in the brain and the failure ofin vitrotranscription studies using OTR promoter constructs to replicate thein vivotranscriptional regulation have raised questions regarding the molecular mechanisms involved in the regulation of the OTR gene by estrogen. Using mice genetically deficient in estrogen receptor a (ERα), we demonstrate that ERα is not necessary for basal OTR synthesis, but is absolutely necessary for the induction of OTR binding in the brain by estrogen.

ISSN:0959-4965    

出版商:OVID    

年代:1998

数据来源: OVID

摘要:

PUTRESCINE has been suggested to have an inhibitory effect on the excitability of the central nervous system. In the present study we found that 2 and 3 weeks after status epilepticus induced by kainic acid, rats had increased concentrations of putrescine (3- and 1.7-fold, respectively) and spermidine (1.6- and 1.4-fold, respectively) in the hippocampus. These animals exhibited a higher susceptibility to pentylentetrazol than the saline group. In addition, several hours after the pentylentetrazol injection, the concentration of putrescine and spermidine increased again in the brain and also in the plasma. In conclusion, increased hippocampal putrescine and spermidine concentrations seem to be linked with a lower threshold of excitability.

ISSN:0959-4965    

出版商:OVID    

年代:1998

数据来源: OVID

摘要:

USING Positron emission tomography (PET), we measured the relative changes in regional cerebral metabolic rate of glucose (rCMRglc) during 2Hz repetitive transcranial magnetic stimulation (rTMS) of the left sensorimotor cortex (SM1) and during imitation of rTMS-induced arm movements. Such stimulation caused an rCMRglc increase of about 8% within the SM1. The relative rCMRglc increase within SM1 was significantly greater in magnitude and larger in area during voluntary imitation of rTMS-induced arm movements. Moreover, the rostral part of the SMA was significantly more activated by voluntary movements than during rTMS. Combining rTMS and PET has the potential to visualize rTMS-related net brain activation, and may open up new possibilities for functional network analysis by comparing willed brain activation with electromagnetic brain activation.

ISSN:0959-4965    

出版商:OVID    

年代:1998

数据来源: OVID

摘要:

FAST associative cellular plasticity of visual cortical cells has been shownin vitrowith electrical stimulation as well asin vivoby pairing of natural stimuli with artificial depolarization. Here we experimentally changed receptive field properties of single cells in the mature cat visual cortex with purely natural associative stimulationin vivo. Single cortical cells expanded their receptive fields within minutes into unresponsive regions and changed their functional receptive field structure for hours after associative co-stimulation of active and primarily unresponsive regions. The effects are interpreted as strengthening of subthreshold synaptic inputs. Repetitive stimulation with the same visual pattern can modify single cell propertiesin vivowithin minutes and may be related to preattentive fast perceptual learning.

ISSN:0959-4965    

出版商:OVID    

年代:1998

数据来源: OVID