Biomedical subjects

Jia-Hua Hu

Publications and source records attributed to Jia-Hua Hu.

3 recordsLinked to original sources

PubMed2004

Cognitive impairment in mice over-expressing gamma-aminobutyric acid transporter 1 (GAT1).

There is increasing evidence that GABAergic system plays an important role in the neural control of learning and memory processes. GAT1 over-expressing mice (NA) were generated, in which GAT1 is under the control of a neuron-specific enolase (NSE) promoter, to investigate effects of GABA transporter on cognitive function. Our results revealed that NA mice displayed cognitive deterioration in associative learning ability and new object recognition retention, compared with the wild-type littermates (WT2). However, the impaired cognitive function of transgenic mice could be rescued after chronic administration of GAT1 selective inhibitor for 6 days. In addition, there was no change of the expression of NMDA receptors in NA mice. Taken together, we show a potentially important role for GAT1 in the neural control of cognitive processes, and indicate great potential for GAT1 as a clinical target of cognitive disorders.

Animals↗

PubMed2003

Decrease of morphine-induced reward effects and withdrawal symptoms in mice overexpressing gamma-aminobutyric acid transporter I.

Morphine addiction has been shown to result from neural adaptations produced by repeated drug exposure, but the mechanism is still unclear. In the present study, we found that gamma-aminobutyric acid (GABA) uptake was increased in mouse brain 120 min after, but not 20 min after, morphine (10 mg/kg, s.c.) injection. We generated GABA transporter I (GAT1)-overexpressing mice to investigate whether the GABAergic system and GABA transporter are involved in morphine-induced reward effects and withdrawal symptoms. Our results revealed that the rewarding effects induced by morphine were significantly decreased in GAT1-overexpressing mice as measured by the conditioned place preference (CPP) paradigm. Moreover, both somatic and vegetative signs of naloxone-induced morphine withdrawal symptoms were substantially reduced in GAT1-overexpressing mice. In addition, the decreased morphine rewarding in transgenic mice could be recovered when mice were coinjected with NO-711 (a GAT1 selective inhibitor) in the CPP paradigm. These findings suggest that the GABAergic system plays an important role in morphine addiction and point to the possibility of developing drugs that target GAT1 and extend the clinical application of opiates.

Adaptation, Physiological↗

PubMed2003

Hyperalgesic effects of gamma-aminobutyric acid transporter I in mice.

The present study focused on the involvement of gamma-aminobutyric acid transporter I (GAT1) in pain. We found that GABA uptake was increased in mouse spinal cord at 20 min and 120 min after formalin injection and in mouse brain at 120 min, but not 20 min, after formalin injection. In addition, the antinociceptive effects of GAT1-selective inhibitors were examined using assays of thermal (tail-flick) and chemical (formalin and acetic acid) nociception in C57BL/6J mice. The GAT1-selective inhibitors, ethyl nipecotate and NO-711, exhibited significant antinociceptive effects in these nociceptive assays. To study further the effects of GAT1 on pain, we used two kinds of GAT1-overexpressing transgenic mice (under the control of a CMV promoter or a NSE promoter) to examine the nociceptive responses in these mice. In the thermal, formalin, and acetic acid assays, both kinds of transgenic mice displayed significant hyperalgesia after nociceptive stimuli. In addition, the micro opioid receptor antagonist naloxone had no influence on nociceptive responses in wild-type and transgenic mice. The results indicate that GAT1 is involved in the regulation of pain processes, and point to the possibility of developing analgesic drugs that target GAT1 other than opioid receptors.

Analgesics, Opioid↗