Temperature dependence on the passive and dynamic electrical parameters of muscle cells.

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.

Quantitation of chronic microwave radiation effects on muscle cell electrical excitable properties: a temperature dependence analysis of the H-H cable and membrane current parameters of irradiated cells.

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.

Quantitation of chronic microwave radiation effects on muscle cell electrical excitable properties: a temperature dependence analysis of the H-H cable and membrane current parameters of irradiated cells

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.

Temperature dependence on the passive and dynamic electrical parameters of muscle cells

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.

Temperature dependence on the passive and dynamic electrical parameters of muscle cells.

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.

Quantitation of chronic microwave radiation effects on muscle cell electrical excitable properties: a temperature dependence analysis of the H-H cable and membrane current parameters of irradiated cells.

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.

Digital interface for bioelectrical data acquisition system.

The action potential digitalized and stored by means of a fast solid state electronic waveform recording system (Digitalizer) can be directly read out on a printer or in a computer for further processing. It has been designed a digital interface allowing the automatization of these bioelectrical data acquisition and printing process.

Digitalizer system and memory for electric transients.

It was designed a fast solid state electronic waveform recording system (Digitalizer), which can record, store and display action potentials or any type of event, either single pulse or repetitive, as a function of time. Above all, its capacity to record fast transients and to give the output in analog and digital form, makes this electronic device more convenient that conventional recorders or single trace oscilloscope systems.

Digitalizer system and memory for electric transients

It was designed a fast solid state electronic waveform recording system (Digitalizer), which can record, store and display action potentials or any type of event, either single pulse or repetitive, as a function of time. Above all, its capacity to record fast transients and to give the output in analog and digital form, makes this electronic device more convenient that conventional recorders or single trace oscilloscope systems.

Digital interface for bioelectrical data acquisition system

The action potential digitalized and stored by means of a fast solid state electronic waveform recording system (Digitalizer) can be directly read out on a printer or in a computer for further processing. It has been designed a digital interface allowing the automatization of these bioelectrical data acquisition and printing process.

Digital interface for bioelectrical data acquisition system.

The action potential digitalized and stored by means of a fast solid state electronic waveform recording system (Digitalizer) can be directly read out on a printer or in a computer for further processing. It has been designed a digital interface allowing the automatization of these bioelectrical data acquisition and printing process.

Digitalizer system and memory for electric transients.

It was designed a fast solid state electronic waveform recording system (Digitalizer), which can record, store and display action potentials or any type of event, either single pulse or repetitive, as a function of time. Above all, its capacity to record fast transients and to give the output in analog and digital form, makes this electronic device more convenient that conventional recorders or single trace oscilloscope systems.

X-radiation actions on the neuromuscular transmission.

The effects of high doses of X-radiation (100 kilorads) on the neuromuscular transmission of isolated sciatic nerve-sartorius muscle preparations of the frog, as evaluated by bioelectrical characteristics, were explored. Intracellular microelectrode recordings after X-irradiation showed that the resting, excitation and action potentials of nerve fibers approaching the synaptic terminal region of the motor end-plate became lessened, and also presented a slower velocity of impulse propagation, earlier than that observed in muscle cells. After forty minutes following the irradiation period, the neuromuscular transmission became blocked, although muscle fibers still responded to direct electrical stimulation. Records taken at the motor end-plate region of muscle cells, demonstrated the presence of postsynaptic miniature end-plate potentials (m.e.p.p.'s), the sequence of which fits closely into a random Poisson distribution. X-irradiation elicited an increase of the rate of m.e.p.p.'s and induced membrane changes over fine terminal nerve branches, leading into a failure to initiate and propagate action potentials. Only as time progressed, this nerve bioelectrical impairment was accompanied by a similar one in muscle cells, associated to the inability to develop contractile tension. The increase of m.e.p.p.'s frequency due to depolarization by a high K+ concentration, of presynaptic nerve membranes of control and irradiated preparations, was reversed by a high Mg+--Ca2+--free media. However, a concentration of Mg2+, which normally reduced quantal release of acetylcholine (ACh), without altering presynaptic nerve membrane potentials, failed to modify the spontaneous basal frequency of m.e.p.p.'s, both in irradiated and control preparations. The findings of the present study suggest that the presynaptic ACh synthesis, storage, and availability for ACh liberation are not early affected by X-rays, i.e. at a time when transmission from nerve to muscle had already failed. On the contrary, the most precocius membrane changes following X-irradiation, seem related to the mechanisms underlying nerve resting, excitation, and action potentials. The smallest presynaptic nerve terminal fibers close to the motor end-plate, are the most radiosensitive portion of the myoneural junction. Indeed, their bioelectric characteristics are early affected by X-rays, resulting in a failure to generate and propagate nerve impulses which lead to a blockade of neuromuscular transmission.

X-radiation actions on the neuromuscular transmission

The effects of high doses of X-radiation (100 kilorads) on the neuromuscular transmission of isolated sciatic nerve-sartorius muscle preparations of the frog, as evaluated by bioelectrical characteristics, were explored. Intracellular microelectrode recordings after X-irradiation showed that the resting, excitation and action potentials of nerve fibers approaching the synaptic terminal region of the motor end-plate became lessened, and also presented a slower velocity of impulse propagation, earlier than that observed in muscle cells. After forty minutes following the irradiation period, the neuromuscular transmission became blocked, although muscle fibers still responded to direct electrical stimulation. Records taken at the motor end-plate region of muscle cells, demonstrated the presence of postsynaptic miniature end-plate potentials (m.e.p.p.’s), the sequence of which fits closely into a random Poisson distribution. X-irradiation elicited an increase of the rate of m.e.p.p.’s and induced membrane changes over fine terminal nerve branches, leading into a failure to initiate and propagate action potentials. Only as time progressed, this nerve bioelectrical impairment was accompanied by a similar one in muscle cells, associated to the inability to develop contractile tension. The increase of m.e.p.p.’s frequency due to depolarization by a high K+ concentration, of presynaptic nerve membranes of control and irradiated preparations, was reversed by a high Mg+--Ca2+--free media. However, a concentration of Mg2+, which normally reduced quantal release of acetylcholine (ACh), without altering presynaptic nerve membrane potentials, failed to modify the spontaneous basal frequency of m.e.p.p.’s, both in irradiated and control preparations. The findings of the present study suggest that the presynaptic ACh synthesis, storage, and availability for ACh liberation are not early affected by X-rays, i.e. at a time when transmission from nerve to muscle had already failed. On the contrary, the most precocius membrane changes following X-irradiation, seem related to the mechanisms underlying nerve resting, excitation, and action potentials. The smallest presynaptic nerve terminal fibers close to the motor end-plate, are the most radiosensitive portion of the myoneural junction. Indeed, their bioelectric characteristics are early affected by X-rays, resulting in a failure to generate and propagate nerve impulses which lead to a blockade of neuromuscular transmission.

X-radiation actions on the neuromuscular transmission.

The effects of high doses of X-radiation (100 kilorads) on the neuromuscular transmission of isolated sciatic nerve-sartorius muscle preparations of the frog, as evaluated by bioelectrical characteristics, were explored. Intracellular microelectrode recordings after X-irradiation showed that the resting, excitation and action potentials of nerve fibers approaching the synaptic terminal region of the motor end-plate became lessened, and also presented a slower velocity of impulse propagation, earlier than that observed in muscle cells. After forty minutes following the irradiation period, the neuromuscular transmission became blocked, although muscle fibers still responded to direct electrical stimulation. Records taken at the motor end-plate region of muscle cells, demonstrated the presence of postsynaptic miniature end-plate potentials (m.e.p.p.s), the sequence of which fits closely into a random Poisson distribution. X-irradiation elicited an increase of the rate of m.e.p.p.s and induced membrane changes over fine terminal nerve branches, leading into a failure to initiate and propagate action potentials. Only as time progressed, this nerve bioelectrical impairment was accompanied by a similar one in muscle cells, associated to the inability to develop contractile tension. The increase of m.e.p.p.s frequency due to depolarization by a high K+ concentration, of presynaptic nerve membranes of control and irradiated preparations, was reversed by a high Mg+--Ca2+--free media. However, a concentration of Mg2+, which normally reduced quantal release of acetylcholine (ACh), without altering presynaptic nerve membrane potentials, failed to modify the spontaneous basal frequency of m.e.p.p.s, both in irradiated and control preparations. The findings of the present study suggest that the presynaptic ACh synthesis, storage, and availability for ACh liberation are not early affected by X-rays, i.e. at a time when transmission from nerve to muscle had already failed. On the contrary, the most precocius membrane changes following X-irradiation, seem related to the mechanisms underlying nerve resting, excitation, and action potentials. The smallest presynaptic nerve terminal fibers close to the motor end-plate, are the most radiosensitive portion of the myoneural junction. Indeed, their bioelectric characteristics are early affected by X-rays, resulting in a failure to generate and propagate nerve impulses which lead to a blockade of neuromuscular transmission.

Automatic microelectrode compensator (AMC).

A solid-state system designed for compensation of asymmetry potentials between microelectrodes, for bioelectric measurements, is described. Advantages over the manual compensator are the following: synchronic compensation of electrodes, application to automatized systems against aging effects in electordes, high speed, and elimination of general muisances of manual circuits. Besides, the system allows to measure digitally the polarization difference and resting membrane potential with precision of +/- 1 mV.

Automatic microelectrode compensator (AMC)

A solid-state system designed for compensation of asymmetry potentials between microelectrodes, for bioelectric measurements, is described. Advantages over the manual compensator are the following: synchronic compensation of electrodes, application to automatized systems against aging effects in electordes, high speed, and elimination of general muisances of manual circuits. Besides, the system allows to measure digitally the polarization difference and resting membrane potential with precision of +/- 1 mV.

Automatic microelectrode compensator (AMC).

A solid-state system designed for compensation of asymmetry potentials between microelectrodes, for bioelectric measurements, is described. Advantages over the manual compensator are the following: synchronic compensation of electrodes, application to automatized systems against aging effects in electordes, high speed, and elimination of general muisances of manual circuits. Besides, the system allows to measure digitally the polarization difference and resting membrane potential with precision of +/- 1 mV.