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1.
IEEE Eng Med Biol Mag ; 6(1): 52-7, 1987.
Artigo em Inglês | MEDLINE | ID: mdl-19493823
2.
Acta Physiol Lat Am ; 29(1): 15-43, 1979.
Artigo em Inglês | MEDLINE | ID: mdl-318091

RESUMO

Measurements of the temperature dependence in the range from 10 C to 30 C on the passive and dynamic electrical properties of single frog muscle cell following Arrhenius relation have been made. The propagated responses (V-t) and conduction velocity theta were analyzed following the H-H propagated cable equation. The ionic current-membrane potential relationship (I-t) was calculated from the phase-plane trajectory analysis (V-V) of the action potential curve (V-t). All the rate and time constants of the excitation and propagation processes kr, kNa, kK, tau Na, tau K, the negative conductance (-gNa) and the ionic conductances gNa, gK, influencing the evolution of the curves (V-t), (V-V) and (I-V) are correlated. The magnitudes of the resting (Vr) and action potential amplitude (Vs), the excitation potential (V*), the negative after potential (Vn), and the sodium equilibrium potential (VNa); the magnitudes of the maximum rate of rise and fall of the spike (V+) and (V-) and those corresponding to the inward INa and outward IK ionic currents, were analyzed. Two general classes of findings were obtained. One group of action potential parameters theta, V+, V-, Vn, kr, kNa, kK, tau Na, tau K, -gNa, gNa, gK, INa and IK is strongly temperature dependent with Q 10 S approximately 2 and energy of activation E approximately 10 kcal/mole. The other group of parameters, Gm (passive conductance), Cm (capacitance), tau, Vr, V*, Vs, and VNa are slightly temperature dependent, with Q10's lower than 1.4. This study contributes deeply to the analysis of temperature effects on the electrical cell responses to adequate stimuli. This temperature dependence analysis was designed to detect possible "masked" actions of microwave radiation on cell membrane functions.


Assuntos
Músculos/fisiologia , Temperatura , Potenciais de Ação , Animais , Condutometria , Eletrofisiologia , Potenciais da Membrana , Modelos Biológicos , Potássio/metabolismo , Rana pipiens/fisiologia , Sódio/metabolismo
3.
Acta Physiol Lat Am ; 29(1): 45-71, 1979.
Artigo em Inglês | MEDLINE | ID: mdl-318092

RESUMO

Frogs Rana pipiens maintained under constant laboratory environmental conditions were subjected daily to chronic microwave exposure with pulsed microwave (2.88 GHZ) at a power density of 10 mW/cm2, during 0.1 hour, for periods up to 100 days. The whole body Specific Absorption Rate (SAR) was of 1.5 mW/g per 1 mW/cm2. The passive and dynamic electrical parameters of sartorius muscle cells from control and irradiated frogs as a function of temperature in the range from 10 C to 30 C, have been analyzed. This temperature dependence analysis, presented in another work, was planned to be used in this paper for detecting those possible "masked" chronic microwave effects in complex membrane mechanisms highly temperature sensitive, and tightly related to the excitation and propagation of bioelectrical responses. The temperature dependence of the passive (Vr, Gm, Cm, and tau) and the active cell electrical parameters (theta, V*, Vs, VNa, Vn, V+, V-, kr, kNa, kK, tau Na, tau K, -gNa, gNa, gK, INa, and IK) was not altered by chronic microwave exposure. The striking observation reported in another work, about the presence of two groups of cell electrical parameters, characterized by their dependence with temperature, was reproduced on the irradiated muscle cells. Results have indicated that there was not muscle cell cumulative bioeffects resulting from microwave exposure to 10 mW/cm2, over a 0.1 hour period.


Assuntos
Micro-Ondas , Músculos/efeitos da radiação , Temperatura , Potenciais de Ação/efeitos da radiação , Animais , Eletrofisiologia , Potenciais da Membrana/efeitos da radiação , Músculos/fisiologia , Rana pipiens/fisiologia
4.
Acta physiol. latinoam ; 29(1): 45-71, 1979.
Artigo em Espanhol | LILACS-Express | BINACIS | ID: biblio-1158615

RESUMO

Frogs Rana pipiens maintained under constant laboratory environmental conditions were subjected daily to chronic microwave exposure with pulsed microwave (2.88 GHZ) at a power density of 10 mW/cm2, during 0.1 hour, for periods up to 100 days. The whole body Specific Absorption Rate (SAR) was of 1.5 mW/g per 1 mW/cm2. The passive and dynamic electrical parameters of sartorius muscle cells from control and irradiated frogs as a function of temperature in the range from 10 C to 30 C, have been analyzed. This temperature dependence analysis, presented in another work, was planned to be used in this paper for detecting those possible [quot ]masked[quot ] chronic microwave effects in complex membrane mechanisms highly temperature sensitive, and tightly related to the excitation and propagation of bioelectrical responses. The temperature dependence of the passive (Vr, Gm, Cm, and tau) and the active cell electrical parameters (theta, V*, Vs, VNa, Vn, V+, V-, kr, kNa, kK, tau Na, tau K, -gNa, gNa, gK, INa, and IK) was not altered by chronic microwave exposure. The striking observation reported in another work, about the presence of two groups of cell electrical parameters, characterized by their dependence with temperature, was reproduced on the irradiated muscle cells. Results have indicated that there was not muscle cell cumulative bioeffects resulting from microwave exposure to 10 mW/cm2, over a 0.1 hour period.

5.
Acta physiol. latinoam ; 29(1): 15-43, 1979.
Artigo em Espanhol | LILACS-Express | BINACIS | ID: biblio-1158616

RESUMO

Measurements of the temperature dependence in the range from 10 C to 30 C on the passive and dynamic electrical properties of single frog muscle cell following Arrhenius relation have been made. The propagated responses (V-t) and conduction velocity theta were analyzed following the H-H propagated cable equation. The ionic current-membrane potential relationship (I-t) was calculated from the phase-plane trajectory analysis (V-V) of the action potential curve (V-t). All the rate and time constants of the excitation and propagation processes kr, kNa, kK, tau Na, tau K, the negative conductance (-gNa) and the ionic conductances gNa, gK, influencing the evolution of the curves (V-t), (V-V) and (I-V) are correlated. The magnitudes of the resting (Vr) and action potential amplitude (Vs), the excitation potential (V*), the negative after potential (Vn), and the sodium equilibrium potential (VNa); the magnitudes of the maximum rate of rise and fall of the spike (V+) and (V-) and those corresponding to the inward INa and outward IK ionic currents, were analyzed. Two general classes of findings were obtained. One group of action potential parameters theta, V+, V-, Vn, kr, kNa, kK, tau Na, tau K, -gNa, gNa, gK, INa and IK is strongly temperature dependent with Q 10 S approximately 2 and energy of activation E approximately 10 kcal/mole. The other group of parameters, Gm (passive conductance), Cm (capacitance), tau, Vr, V*, Vs, and VNa are slightly temperature dependent, with Q10’s lower than 1.4. This study contributes deeply to the analysis of temperature effects on the electrical cell responses to adequate stimuli. This temperature dependence analysis was designed to detect possible [quot ]masked[quot ] actions of microwave radiation on cell membrane functions.

6.
Acta Physiol Lat Am ; 29(1): 15-43, 1979.
Artigo em Inglês | BINACIS | ID: bin-47005

RESUMO

Measurements of the temperature dependence in the range from 10 C to 30 C on the passive and dynamic electrical properties of single frog muscle cell following Arrhenius relation have been made. The propagated responses (V-t) and conduction velocity theta were analyzed following the H-H propagated cable equation. The ionic current-membrane potential relationship (I-t) was calculated from the phase-plane trajectory analysis (V-V) of the action potential curve (V-t). All the rate and time constants of the excitation and propagation processes kr, kNa, kK, tau Na, tau K, the negative conductance (-gNa) and the ionic conductances gNa, gK, influencing the evolution of the curves (V-t), (V-V) and (I-V) are correlated. The magnitudes of the resting (Vr) and action potential amplitude (Vs), the excitation potential (V*), the negative after potential (Vn), and the sodium equilibrium potential (VNa); the magnitudes of the maximum rate of rise and fall of the spike (V+) and (V-) and those corresponding to the inward INa and outward IK ionic currents, were analyzed. Two general classes of findings were obtained. One group of action potential parameters theta, V+, V-, Vn, kr, kNa, kK, tau Na, tau K, -gNa, gNa, gK, INa and IK is strongly temperature dependent with Q 10 S approximately 2 and energy of activation E approximately 10 kcal/mole. The other group of parameters, Gm (passive conductance), Cm (capacitance), tau, Vr, V*, Vs, and VNa are slightly temperature dependent, with Q10s lower than 1.4. This study contributes deeply to the analysis of temperature effects on the electrical cell responses to adequate stimuli. This temperature dependence analysis was designed to detect possible [quot ]masked[quot ] actions of microwave radiation on cell membrane functions.

7.
Acta Physiol Lat Am ; 29(1): 45-71, 1979.
Artigo em Inglês | BINACIS | ID: bin-47004

RESUMO

Frogs Rana pipiens maintained under constant laboratory environmental conditions were subjected daily to chronic microwave exposure with pulsed microwave (2.88 GHZ) at a power density of 10 mW/cm2, during 0.1 hour, for periods up to 100 days. The whole body Specific Absorption Rate (SAR) was of 1.5 mW/g per 1 mW/cm2. The passive and dynamic electrical parameters of sartorius muscle cells from control and irradiated frogs as a function of temperature in the range from 10 C to 30 C, have been analyzed. This temperature dependence analysis, presented in another work, was planned to be used in this paper for detecting those possible [quot ]masked[quot ] chronic microwave effects in complex membrane mechanisms highly temperature sensitive, and tightly related to the excitation and propagation of bioelectrical responses. The temperature dependence of the passive (Vr, Gm, Cm, and tau) and the active cell electrical parameters (theta, V*, Vs, VNa, Vn, V+, V-, kr, kNa, kK, tau Na, tau K, -gNa, gNa, gK, INa, and IK) was not altered by chronic microwave exposure. The striking observation reported in another work, about the presence of two groups of cell electrical parameters, characterized by their dependence with temperature, was reproduced on the irradiated muscle cells. Results have indicated that there was not muscle cell cumulative bioeffects resulting from microwave exposure to 10 mW/cm2, over a 0.1 hour period.

8.
Acta Physiol Lat Am ; 28(6): 271-307, 1978.
Artigo em Inglês | MEDLINE | ID: mdl-263161

RESUMO

The equation for membrane potential (V) of the squid giant axon or some muscle cells, which is the heart of the Hodgkin-Huxley model for the action potential, can be written in three ways: first, as a partial differential equation in time and space; second, as an ordinary differential equation in time, assuming uniform wave propagation for the action potential, and third, as an even simpler ordinary differential equation for the potential at a point, so-called "space clamp" conditions. Solutions were computed for the first two of these equations, at three different temperatures, and the results compared. Temperature dependence of the appropriate parameters was calculated from a simple exponential relationship. Significant changes in the quantitative predictions of the model were found as the temperature was changed from 6.3 C to 18.5 C. Phase-plane (V v V, I v V) analysis has been used to examine the nature of these differences.


Assuntos
Potenciais de Ação , Axônios/fisiologia , Potenciais da Membrana , Temperatura , Animais , Computadores , Decapodiformes , Modelos Neurológicos
9.
Acta physiol. latinoam ; 28(6): 271-307, 1978.
Artigo em Espanhol | LILACS-Express | BINACIS | ID: biblio-1158603

RESUMO

The equation for membrane potential (V) of the squid giant axon or some muscle cells, which is the heart of the Hodgkin-Huxley model for the action potential, can be written in three ways: first, as a partial differential equation in time and space; second, as an ordinary differential equation in time, assuming uniform wave propagation for the action potential, and third, as an even simpler ordinary differential equation for the potential at a point, so-called [quot ]space clamp[quot ] conditions. Solutions were computed for the first two of these equations, at three different temperatures, and the results compared. Temperature dependence of the appropriate parameters was calculated from a simple exponential relationship. Significant changes in the quantitative predictions of the model were found as the temperature was changed from 6.3 C to 18.5 C. Phase-plane (V v V, I v V) analysis has been used to examine the nature of these differences.

10.
Acta Physiol Lat Am ; 28(6): 271-307, 1978.
Artigo em Inglês | BINACIS | ID: bin-47343

RESUMO

The equation for membrane potential (V) of the squid giant axon or some muscle cells, which is the heart of the Hodgkin-Huxley model for the action potential, can be written in three ways: first, as a partial differential equation in time and space; second, as an ordinary differential equation in time, assuming uniform wave propagation for the action potential, and third, as an even simpler ordinary differential equation for the potential at a point, so-called [quot ]space clamp[quot ] conditions. Solutions were computed for the first two of these equations, at three different temperatures, and the results compared. Temperature dependence of the appropriate parameters was calculated from a simple exponential relationship. Significant changes in the quantitative predictions of the model were found as the temperature was changed from 6.3 C to 18.5 C. Phase-plane (V v V, I v V) analysis has been used to examine the nature of these differences.

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