Membrane potential change

Identity of action. The proposed NT must produce effects postsynaptically which are identical physiologically (appropriate membrane potential changes) and pharmacologically (sensitivity to antagonists) to that produced by neuronal stimulation and the relased endogenous NT. 

The electricity-producing system of electric fishes is built as follows. A large number of flat cells (about 0.1 mm thick) are stacked like the flat unit cells connected in series in a battery. Each cell has two membranes facing each other. The membrane potentials of the two membranes compensate for each other. In a state of rest, no electrostatic potential difference can be noticed between the two sides of any cell or, consequently, between the ends of the stack. The ends of nerve cells come up to one of the membranes of each cell. When a nervous impulse is applied from outside, this membrane is excited, its membrane potential changes, and its permeability for ions also changes. Thus, the electrical symmetry of the cell is perturbed and a potential difference of about 0.1 V develops between the two sides. Since nervous impulses are applied simultaneously to one of the membranes in each cell, these small potential differences add up, and an appreciable voltage arises between the ends of the stack. 

Owing to the small changes induced by typical membrane potentials, the voltage sensitivity may be accurately expressed as a sum of independent terms. A fractional change in signal (absorbance or fluorescence) per 100 mV of applied membrane potential change was given by Fromherz et al. [66] as ... 

Rusu CF, Lanig H, Othersen OG, Kryschi C, Clark T (2008) Monitoring biological membrane-potential changes a Cl QM/MM study. J Phys Chem B 112(8) 2445-2455... 

Figure 5.3. (a) Example for a compound used in the study of membrane potentials and (b) principle of funcboning of visualizing nerve pulses in a living cell. When a nerve pulse passes, the membrane potential changes, and this induces a change in the fluorescence intensity of the probe. The temporal and spatial profile of these changes can be followed by time-resolved methods. 

Seligmann BE, Fletcher MR Gallin JI Histamine modulation of human neutrophil oxidative metabolism, locomotion, degranulation, and membrane potential changes. J Immunol 1983 130 1902-1909. 

Figure 3. Schematic representations of models based on charge separation for membrane potential changes induced by host-guest complexation at liquid membrane surfaces, (a) Membrane potential change induced by a cationic guest, (b) Membrane potential change induced by an anionic guest (reproduced with permission of Elsevier Science Ltd. from Comprehensive Supramolecular Chemistry, 1996, Vol. 2,p. 176).

H. P. Meissner and M. Preissler Ionic mechanisms of the glucose-induced membrane potential changes in jS-cells. Horn. Metab. Res. 1980,10[Suppl.] 91 —99. 

Al. Aizawa, M., Kato, S., and Suzuki, S., Immunoresponsive membrane. I. Membrane potential change associated with an immunochemical reaction between membrane-bound antigen and free antibody. J. Membr. Sci. 2, 125-132 (1977). 

Nastuk, W.L. Membrane potential changes at a single muscle end plate produced by transitory application of acetylcholine with an electrically controlled microjet. 

Thus, we expect the cytosol to be electrically negative with respect to the external bathing solution, as is indeed the case. In fact, the measured value of the electrical potential difference across the plasma membrane of N. translucens is —138 mV at 20°C (Table 3-1). This close agreement between the observed electrical potential difference and that calculated from the Goldman equation supports the contention that the membrane potential is a diffusion potential. This can be checked by varying the external concentration of K+, Na+, and/or Cl and seeing whether the membrane potential changes in accordance with Equation 3.20. 

The membrane potential changes from —100 mV (initial value) to —129 mV during the time that the work is done, so the average difference in electrical potential across the membrane is -115 mV Hence,by Equation 3.1, the electrical work is about... 

Fig. 23. Experimental set-up for measuring light induced membrane potential change [51]. A, amplifier B, recorder E, saturated calomel electrode L, light source M, membrane E, rubber packing S, magnetic stirrer bar...

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