2. With ]egarding to the relatively slow rise times of the IPSCs, we think there are two possibilities. First, more or less, the IPSCs will be unavoidably filtered by its process structure ly their fast rise phase(see the reply 1a)- ut simulation with typical values of the parameters used above 90%rise-time is abeut 0, 5-ms for IP时算二, m BC soma. However, when the 10-90% rise time is about 2.5 ms the increase is less than 10%/Therefore. itseems electrical filtering ter the slow rise times of IPSCs observed in our work 6-7 4e is due to thet int 和+ BCs, just as suggested for glycine 203的2/ eceptors in the neuron of the inferior colliculus(Backus, Frech and Karushaar Perez-Leon, Wassle and Backus, J Neurophysiol 2001)/performing on mouse amacrine cells! They -found-that,-ony compact amacrine cells, the 10-90% nise(Lt me of glycinergic IPSCs is about 2.4 ms, while that of GABAergic IPSCs is much less(see pages 1632, 1637-1639 of the paper). They thought that the slow rise time is not due to process filtering, but may be due to synaptic properties, such as slow association rate constants of glycine receptors, slower transmitter exchange rate. which could be due to different morphological properties, different glial ensheathment, or different transmitter reuptake rate and sparse clustering of glycine receptors resulting in a more desynchronized activation of the glycine receptors. Additionally, Maple and Wu(J Physiol 1998) Le ∠ 2出, A∠F
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relationship Po-Im-p /(N), where Im-p is the peak amplitude of the mean IPSC.The weighted mean single-channel conductance (gs) could be derived from the relationship gs=i/(Erev-Vn), where Ere is the reversal potential of glycine receptor mediated chloride currents, and Vi the holding potential. In this study, the equilibrium potential of chloride ions was about-35 mV Statistical analysis was performed using unpaired Student's t test and data were represented as mcans SD B-6lf7 7-4.( RCs " Filtering properties of BCs under voltage-clamp recordings. revaluate the( effect of filtering on the kinetics of IPSCs, we digitally- modeled bullfrog-retinal BCs with NEURON software (Hines and Carnevale. 1997) as following. Bullfrog BC has a soma of about 7 um in diameter, an axon of 50 um long and l um in diameter branching into two processes(30 um in length and 1 um in diameter), and a primary rite of 10-um long and 2 um in diameter branching into two thinner processes um long and l um in diameter/(measured from BC images) Taking a typical input resistance for BCs of 10 G@ when potassium channels were blocked during our experiments. we-can calculate a membrane conductance per unit area of 0. 143 S, o drind e Assume a cytoplasm resistivity of 200 O-cm and a specific membrane capacitance of lyF-cm this would lead to a space constant a)of about 935 ym for d. c and about 197 um for 100 Hz a c. t value much longer than the typical length of uL BC dendrites and axon. For typical glycinergic IPSCs studied in present work with a 10-90% rise time(t)of 1.5-3.5 ms, a decay time constant(tp)of 10-40 ms and a peak amplitude (p)of 5-30 pA, T, and to will be slowed down less than 10%and 5%, respectively, and Ip will be decreased about 7% even when IPSCs were elicited from the end of bc dendrites or axon
response was remarkably potentiated in either low Ca"or in the preser IBMX as well. The increased voltage responses of photoreceptors in low Ca- id definitely enhance Be- - voltaren hanged The above two effects are in opposite signs. Therefore, whether light responses of the second-order neurons are potentiated or suppressed basically depends upon how much the saturation suppression is compensated by th increased d voltage responses of photoreceptors. Possible on for diferential modulation by low Ca" of aina 24 from R- cones and (-canes to BCs It was previously reported that low Ca suppressed the G-cone-driven responses of the cone horizontal cell more substantially than the R-cone-driven ones. This observation was accounted for by that the reduction in the synaptic strength between R-cones and cone horizontal cells due to saturation suppressio couid be compensated to a targer extent by the more potentiated one signal in low C, as compared to the G-cone signal [51]. This difference in compensation extent could Diay be sponsible for differential modulation of R-cone and G-cone-driven BC responses( Fig. I and 2).This explanation did not exclude other mechanisms that may involved in the above different effects of low Cal, sueh as R-cone and-e-cones may operate al different pathway for the signal input to cone oN BCs as it had been reported in Lotype horizontal cells. However, this point-remaine te be 7 ∠y47
本研究室科研论文撰写的程序 7.导师与学生对第三稿进行讨论后,由导师拟 就第四稿,交回学生再评论和修改。 8.对学生的评论和修改意见作认真考虑后,拟 就第五稿(半定稿),请学生评论、修改。 9.导师最后定稿(第六稿),并对英文作仔细 润色。 10.由学生严格按投寄杂志的要求整理定稿、送 审
7. 导师与学生对第三稿进行讨论后，由导师拟 就第四稿，交回学生再评论和修改。 8. 对学生的评论和修改意见作认真考虑后，拟 就第五稿（半定稿），请学生评论、修改。 9. 导师最后定稿（第六稿），并对英文作仔细 润色。 10.由学生严格按投寄杂志的要求整理定稿、送 审。 本研究室科研论文撰写的程序