Biomedical subjects

Sun-Kai Ma

Publications and source records attributed to Sun-Kai Ma.

3 recordsLinked to original sources

PubMed2007

Reduced aggression in mice lacking GABA transporter subtype 1.

Dysregulation of the brain GABAergic system has been implicated in the pathophysiology of violence and aggression. As a key regulator of central GABAergic activity, dysfunction of the GABA transporter subtype 1 (GAT1) represents a potential mechanism mediating pathologic aggression. We provide evidence that GAT1-/- mice and GAT1+/- mice exhibit lower aggressive behavior both in home cage resident-intruder test and neutral arena resident-intruder test, compared to wild-type mice (GAT1+/+). The pharmacologic effects of the GAT1 inhibitor, tiagabine and the GABA(A) receptor antagonist, bicuculline have been assessed in GAT1+/+ mice: tiagabine inhibits attacks but bicuculline induces attacks. Compared to GAT1+/- and +/+ mice, the GAT1-/- mice displayed a normal circadian pattern of home cage activity, but more activity overall. Meanwhile, reduced testosterone concentration was found in GAT1-/- mice compared to GAT1+/+ mice but not in GAT1+/+ mice treated with tiagabine, suggesting that testosterone is not directly involved in GAT1 mediated aggressive behavior regulation. These results showed that GAT1 is an important target involved in the regulation of aggressive behavior in mice, and long-term dysfunction of GAT1 may also result in the alteration of testosterone secretion.

Aggression↗

PubMed2006

Mice with genetically altered GABA transporter subtype I (GAT1) expression show altered behavioral responses to ethanol.

It is widely accepted that the GABAergic system plays an important role in the action of ethanol in vivo. GABA transporter subtype 1 (GAT1) constructs high affinity reuptake sites in the CNS and regulates GABAergic transmissions. In this study, mice lacking the GAT1 were developed by homologous recombination. Both hetero- and homozygous GAT1 mutant mice were tested for ethanol, saccharin or quinine consumption, ethanol-conditioned place preference, ethanol-conditioned taste aversion, ethanol-simulated motor activity, and ethanol-induced sedation/hypnosis. The GAT1(-/-) mice showed decreased ethanol aversion and ethanol reward, and insensitivity to both the sedative/hypnotic and the motor stimulant effects of ethanol, along with increased avoidance of quinine preference and consumption. GAT1(+/-) mice showed significantly increased consumption of ethanol and saccharin, however, enhanced the rewarding and preference effect of ethanol, increased avoidance of quinine, and higher sensitivity to the motor stimulant effect of ethanol. These results demonstrate that GAT1, perhaps in a bi-directional way, modulates some behavioral effects of ethanol. The GAT1 mutant mice provided us a very useful model to investigate the mechanisms of ethanol action in vivo.

Analgesics, Non-Narcotic↗

PubMed2005

[Generation of transgenic mice for hygromycin and neomycin resistance genes and studies on transgene expression].

To generate transgenic mice in which both hygromycin (hyg) and neomycin (neo) resistance genes are expressed in murine fibroblast cells (MEFs), which are required for conditional gene knock-out and screening of drug resistant ES cell clones. To construct HygR-neoR expression vector, pTK-hygR-pA and PGK-neoR-pA were cloned into pBluescript vector. DNA fragments of tandem genes ( 4245bp ) were prepared by Kpn I and Xba I digestion and transgene was microinjected into pronucleus of zygotes to generate transgenic mice. Transgenic mice were identified by PCR and Southern blot; expression of hygR and neoR gene transcripts were detected by RT-PCR. 7 founder mice carrying hyg-neo resistant genes were obtained and 6 transgenic mouse lines were successfully established. The hygR and neoR gene transcripts were detected in the liver and/or ovary of transgenic mice from hn30, hn33, hn66 and hn67 mouse lines. In MEFs isolated from the mice of line hn66 and hn30, expression of hyg and neo resistant genes was also detectable. Transgenic mouse lines expressing two anti-drug genes have been established. The hyg and neo resistant gene transcripts were detected in the MEFs of two transgenic mouse lines.

Animals↗