ABSTRACT
OBJECTIVE: To investigate the effect of beryllium sulfate( BeSO_4) on apoptosis of human embryonic lung fibroblast( MRC-5 cell). METHODS: MRC-5 cells were cultured in vitro and randomly divided into 6 groups: a control group,a low-,medium- and high-dose BeSO_4 group,an antagonist group,and an activator group. The former 4 groups were given final concentrations of 0,1,10 and 100 μmol / L of BeSO_4,respectively. The combined treatment of BeSO_4and2-aminoethoxydiphenyl borate( 10 μmol / L final concentration) was used in the antagonist group. The combined treatment of BeSO_4 and inositol triphosphate( IP3)( 10 μmol / L final concentration) was used in the activator group. After 24 and48 hours of culture,the cells were harvested. The apoptosis of MRC-5 cells was detected by flow cytometry. The intracellular calcium ion( Ca~(2+)) was detected using laser scanning confocal microscope. Quantitative real-time polymerase chain reaction was used to detect the relative expression of IP_3RⅢ and B-cell lymphoma-2( BCL-2) mRNA and the protein expression of IP_3RⅢ and IP3 were detected by enzyme-linked immunosorbent assay. RESULTS: The apoptosis rates of cells in the 3 BeSO_4 dose groups at the time points of 24 and 48 hours were lower than those in the control group at the same time points( P < 0. 05). The apoptosis rate of the antagonist group was lower than those in medium-dose BeSO_4 group and control group at the same time points( P < 0. 05). At the time point of 48 hours,the apoptosis rate of the activator group was lower than that of control group( P < 0. 05) and higher than that of the medium-dose BeSO_4group( P < 0. 05). As for the Ca~(2+)concentration at time point of 24 hours,the low-dose BeSO_4 group was lower than the control group( P < 0. 05),and the high-dose BeSO_4 group was higher than the control group( P < 0. 05). The Ca~(2+)concentrations at time point of 48 hours in the medium- and high-dose BeSO_4 groups were lower than that in the control group( P < 0. 05). Compared with the medium-dose BeSO_4 group and control group at time points of 24 and 48 hours,the Ca~(2+)concentrations in the antagonist group decreased( P < 0. 05),while thoes of the activator group increased( P < 0. 05). The expression of BCL-2and IP_3RⅢmRNA in the 3 BeSO_4 groups,the activator and antagonist group were higher than those of the control group( P <0. 05). The expression of IP3 R Ⅲ protein at the time point of 24 hours in the medium-dose BeSO_4 group,the activator group and the antagonist group were lower than that of control group( P < 0. 05). The expression of IP_3RⅢ protein at the time point of 48 hours,the high-dose BeSO_4 group was lower than the control group( P < 0. 05); the activator and antagonist groups were higher than the medium-dose BeSO_4group( P < 0. 05). The expression of IP3 protein in the lowand medium-dose BeSO_4 groups and the activator group were higher than that in the control group( P < 0. 05). The expression of IP3 protein in activator group was higher than the medium-dose group( P < 0. 05). CONCLUSION: BeSO_4 might change the Ca~(2+)concentration and inhibite the apoptosis of MRC-5 cell through regulating the IP3 R / Ca~(2+)pathway,IP3 can improve the decrease of Ca~(2+)concentration in MRC-5 cells induced by BeSO_4.
ABSTRACT
<p><b>OBJECTIVE</b>To determine whether the convergences of tactile information also occur at thalamic ventroposterolateral nucleus in rats, we investigated the properties of tactile responses of the thalamic ventroposterolateral nucleus in rats.</p><p><b>METHODS</b>Unit responses were recorded extracellularly from thalamic ventroposterolateral nucleus in anesthetized rats.</p><p><b>RESULTS</b>Among 156 neurons examined, 140 neurons (89.7%) had the single, continual and small receptive fields, and 16 neurons (10.3%) had two discrete receptive fields. Some neurons?exhibited different responses to the same intensity stimulation which delivered to different points in their receptive fields. In addition, 4.5% neurons (n = 7) responded only to locomotive stimulation but?not to a punctiform tactile stimulation.</p><p><b>CONCLUSION</b>The majority of neurons in ventroposterolateral nucleus of rats have the spatial, temporal and submodal characteristics of cutaneous receptors, while the minority of neurons exhibit the responses of interaction of different peripheral receptors. Therefore, it is concluded that there are convergences of tactile information at the ventroposterolateral nucleus of rats.</p>
Subject(s)
Animals , Male , Rats , Neural Pathways , Cell Biology , Physiology , Neurons , Cell Biology , Physiology , Physical Stimulation , Rats, Sprague-Dawley , Skin , Thalamic Nuclei , Cell Biology , Physiology , TouchABSTRACT
Experiments were performed on Sprague Dawley rats with multibarrel microelectrode technique. The effects of acoustic response of A I cortex neurons produced by electrical stimulation of lateral amygdaloid nucleus (LA) and the influence of GABA were observed. Experimental results showed that iontophoretic administration of GABA caused a pronounced inhibition of the electrical activity of A-I neurons. Blockade of GABA(A) with bicuculline (BIC) facilitated the acoustic response. The acoustic response of A-I neurons was inhibited when the LA was stimulated. Iontophoretic application of GABA resulted in a similar inhibitory effect as that of LA stimulation. Blockade of GABA(A) with bicuculline reversed the inhibitory effect of LA stimulation on the acoustic response of A-I neurons. In contrast, application of strychnine, a glycine receptor antagonist, could not reverse the inhibitory effect of LA. Baclofen, a GABA(B) agonist, did not affect the acoustic response of the auditory neurons. These results indicate that GABA is the ultimate transmitter which mediates the LA stimulation-induced inhibition of the acoustic response of A-I neurons in rats, possibly via the GABA(A) receptor.