2.5 Results and Conclusions
163
There were developed and tested two types of optical cameras for holographic
study of structural and functional changes in the aging nerve and nerve fiber preparations under gaseous and hydrostatic pressure that make it possible to implement
high pressure modes in broad limits from 0 to 200 atm.
To estimate the alterations of the refractive index and shape of the isolated nerve
and muscle tissue preparations under high gaseous pressure, the holographic method
was developed that makes it possible to obtain interferograms of the microobjects
under study with magnification of 140× in the pressure range of 0:5 atm. There
were obtained finite band holographic interferograms of the nerve and muscle fibers
under normal conditions and under high pressure of 4 atm. with the accuracy of
path difference measurement of interfering beams λ/30. The implementation of this
method showed in a number of cases the profile changes of phase incursions in
a single muscle fiber under pressure application that is indicative of its possible
structural changes.
The adaptation of the electrophysiologically controlled laser diffractometry
method for the study of function alteration of muscle fiber under aging hyperbary proved that pressure application (~3.5 atm.) can lead to spasmodic irreversible
excitability oppression. On the whole, the fibers under the gaseous pressure were
characterized by stronger marked excitability fluctuations and had statically lesser
time of preparation aging than in the control.
Using the holographic interference microscopy method adapted to studying the
degree of compression of isolated nerve preparation under high hyperbary (up to 200
atm.), the absence of mechanical damaging effect of the high hydrostatic pressure
(R/R ≤ 10
−5 ) was ascertained that is indicative of the fact that failures of membrane
processes are likely to underlie changes of nerve functions under these conditions.
In order to study the changes in the refractive index of the isolated nerve
under hydrostatic pressure, there was developed the method of obtaining hologram of semitransparent diffusely scattering objects with a varying microstructure
and having cylindrical symmetry. The method is based on the spatial filtration of
Fourier-spectrum of the radiation passed through the object.
During the electrophysiological study of excitability of isolated nerve tissue preparations, it was found that the hyperbary impact (air up to 3.5 atm.) is oppressed by
electrogenesis that provides generation and conduction of action potential caused
by electrical stimulation of isolated nerve fibers as well as nerve fibers as a part of
the isolated sciatic nerve of a brown frog. This manifests in action potential attenuation of an isolated nerve fiber in response to the application with pressure. The
impact of the gaseous pressure (3.5 atm.) leads to irreversible electrogenesis loss
of single fibers. The alteration of the nerve fiber compound action potential of the
single nerve in response to the hyperbary impact has a more complex character: The
first applications on the fresh-separated nerve can influence slightly the electrogenesis that however intensifies as the time of preparation aging increases. This leads
to action potential amplitude contraction, an increase of dispersion of latent period
and length, growth of stimulation threshold values that finally leads to the loss of
ability to generate the action potential in response to the electrical stimulation. This
occurs significantly earlier than in conditions of aging without any impact on the
163
There were developed and tested two types of optical cameras for holographic
study of structural and functional changes in the aging nerve and nerve fiber preparations under gaseous and hydrostatic pressure that make it possible to implement
high pressure modes in broad limits from 0 to 200 atm.
To estimate the alterations of the refractive index and shape of the isolated nerve
and muscle tissue preparations under high gaseous pressure, the holographic method
was developed that makes it possible to obtain interferograms of the microobjects
under study with magnification of 140× in the pressure range of 0:5 atm. There
were obtained finite band holographic interferograms of the nerve and muscle fibers
under normal conditions and under high pressure of 4 atm. with the accuracy of
path difference measurement of interfering beams λ/30. The implementation of this
method showed in a number of cases the profile changes of phase incursions in
a single muscle fiber under pressure application that is indicative of its possible
structural changes.
The adaptation of the electrophysiologically controlled laser diffractometry
method for the study of function alteration of muscle fiber under aging hyperbary proved that pressure application (~3.5 atm.) can lead to spasmodic irreversible
excitability oppression. On the whole, the fibers under the gaseous pressure were
characterized by stronger marked excitability fluctuations and had statically lesser
time of preparation aging than in the control.
Using the holographic interference microscopy method adapted to studying the
degree of compression of isolated nerve preparation under high hyperbary (up to 200
atm.), the absence of mechanical damaging effect of the high hydrostatic pressure
(R/R ≤ 10
−5 ) was ascertained that is indicative of the fact that failures of membrane
processes are likely to underlie changes of nerve functions under these conditions.
In order to study the changes in the refractive index of the isolated nerve
under hydrostatic pressure, there was developed the method of obtaining hologram of semitransparent diffusely scattering objects with a varying microstructure
and having cylindrical symmetry. The method is based on the spatial filtration of
Fourier-spectrum of the radiation passed through the object.
During the electrophysiological study of excitability of isolated nerve tissue preparations, it was found that the hyperbary impact (air up to 3.5 atm.) is oppressed by
electrogenesis that provides generation and conduction of action potential caused
by electrical stimulation of isolated nerve fibers as well as nerve fibers as a part of
the isolated sciatic nerve of a brown frog. This manifests in action potential attenuation of an isolated nerve fiber in response to the application with pressure. The
impact of the gaseous pressure (3.5 atm.) leads to irreversible electrogenesis loss
of single fibers. The alteration of the nerve fiber compound action potential of the
single nerve in response to the hyperbary impact has a more complex character: The
first applications on the fresh-separated nerve can influence slightly the electrogenesis that however intensifies as the time of preparation aging increases. This leads
to action potential amplitude contraction, an increase of dispersion of latent period
and length, growth of stimulation threshold values that finally leads to the loss of
ability to generate the action potential in response to the electrical stimulation. This
occurs significantly earlier than in conditions of aging without any impact on the