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Aims: γ-aminobutyric acid (GABA), the principal inhibitory neurotransmitter, acts on GABA receptors to play an important role in the modulation of macrophage functions. The present study examined the effects of GABA and a GABA receptor agonist on modulating cholesterol-metabolism-associated molecules in human monocyte-derived macrophages (HMDMs). Methods: ORO stain, HPLC, qRT-PCR, Western blot and EMSA were carried out using HMDMs exposed to ox-LDL with or without GABAergic agents as the experimental model. Results: GABA and topiramate reduced the percentage of cholesterol ester in lipid-laden HMDMs by down-regulating SR-A, CD36 and LOX-1 expression and up-regulating ABCA1, ABCG1 and SR-BI expression in lipid-laden HMDMs. The production of TNF-a was decreased in GABA-and topiramate-treated lipid-laden HMDMs, and levels of interleukin (IL)-6 did not change. The activation of two signaling pathways, p38MAPK and NF-γB, was repressed by GABA and topiramate in lipid-laden HMDMs. Conclusion: GABA and topiramate inhibit the formation of human macrophage-derived foam cells and may be a possibility for macrophage targeted therapy of atherosclerotic lesions.

This study will explore the autoantibodies against AT1-receptor and alpha1-adrenergic receptor in patients with hypertension. Forty normotensives and 194 patients with hypertension were recruited for participation in this study. All patients accepted systemic combination drug treatment for antihypertension. According to the treatment results and the definition of refractory hypertension, the patients were divided into two groups: a refractory hypertension group and a non-refractory hypertension group. The epitope of the 2nd extracellular loop of type 1 angiotensin (AT1) receptor and alpha1-adrenergic receptor were synthesized and used as antigens to screen the autoantibodies against AT1-receptor and alpha1-adrenergic receptor by ELISA. The plasma renin activity and concentration of angiotensin II and catecholamine were also examined. The positive rates of the autoantibodies against AT1-receptor and alpha1-adrenergic receptor in patients with hypertension, 26.8% (52/194) and 25.3% (49/194), respectively, were higher than those in normotensives (7.5% and 5%)(p < 0.01). Further investigation showed that the frequencies of the autoantibodies against AT1-receptor and alpha1-adrenergic receptor in patients with refractory hypertension, 42.9% (42/98) and 36.7% (36/98), respectively, were higher than those in patients with non-refractory hypertension under systematic treatment (10.4% and 13.5%)(p < 0.01). The levels of circulating angiotensin II, catecholamine, proteinuria and serum creatine were also higher in the refractory hypertension group than in the non-refractory hypertension group. The findings showed that the frequencies of autoantibodies against AT1-receptor and alpha1-adrenergic receptor were higher in patients with hypertension, particularly in those with refractory hypertension, and that these autoantibodies might play a role in the pathogenesis of hypertension.

Isolated, spontaneously beating rabbit sinoatrial node cells were subjected to longitudinal stretch, using carbon fibers attached to both ends of the cell. Their electrical behavior was studied simultaneously in current-clamp or voltage-clamp mode using the perforated patch configuration. Moderate stretch ( approximately 7%) caused an increase in spontaneous beating rate (by approximately 5%) and a reduction in maximum diastolic and systolic potentials (by approximately 2.5%), as seen in multicellular preparations. Mathematical modeling of the stretch intervention showed the experimental results to be compatible with stretch activation of cation nonselective ion channels, similar to those found in other cardiac cell populations. Voltage-clamp experiments validated the presence of a stretch-induced current component with a reversal potential near -11 mV. These data confirm, for the first time, that the positive chronotropic response of the heart to stretch is, at least in part, encoded on the level of individual sinoatrial node pacemaker cells; all reported data are in agreement with a major contribution of stretch-activated cation nonselective channels to this response.