Permeability as Function of Autonomic Nervous System

Abstract

It is pointed out that the phenomenon of permeability is a function of a definite metabolism, therefore an expression of something alive, dynamic and in no way, static. On the basis of our earlier work, the Straub’s theory of potential poisons, and some muscular disorders as well, it is concluded that the cell membrane is fundamentally important for the function of AcH and ChE, which form a functional unity. The membrane separates the substrate from the encyme, thus preventing the inactivation of the enzyme — in this particulat case the AcH-receptor — from excessive doses of ACH. The Straub’s theory has thus gained a new support. It's arguments, as laid down by Straub 50 years ago, still hold, and this theory becomes, with the improvement of the knowledge of AcH and ChE kinetics, an excellent basis for the study of the function of impulse transmission. Hence it is that ChE is a receptor for AcH.

The work of Greig and his collaborators also showed that ChE is a receptor for AcH. But these authors proceeded a step further showing that olily hydnolysis was necessary for the function of AcH, which, is inconcievable without this receptor. According to Greig and Holland the hydrolysis of AcH, i.e. its function, maintains the cell permeability directing the going out and in of cations. Our preserrt experimental work goes to show that the same what Greig and Holland found to be true for cell membrane also holds for the capillary membrane. Here too the hydrolysis of AcH by its receptor ChE maintains the permeability. We were able to demonstrate this in studyng capillary permeability in vivo and in vitro by means of different methods. Thus we demonstrated a delay in the development of the edema of rats extremities caused by dextran if the prostigmine was given beforehand. This interesting phenomenon was studied histologically as well. It was shown also that the administration of prostigmine to the rat prevents the fluoresceine to diffuse in the eye. This delay can also be obtained with insulin which makes possible augmented accumulation of AcH through the enhancement of Cholin-acetylase activity. By the use of prostigmine we were also able to prevent the diffusion of trypan-blue out of skin capillaries. On rabbits in vivo we demonstrated that the administration of prostigmine prevented urea to diffuse out of capil­aries i.e. to enter the cells. The same effect was obtained with digitoxin, which reduces permeabillity like many other sterines. The experiments with the prostigmine in vitro on the isolated joint capsula of the calf produced the reverse result, namely an increased permeability, because the prostigmine in vitro inhibits the true ChE which results in a decrease in the activity of the system ChE—AcH, whereas in vivo the activity of this system is increased owing to the inhibition of pseudo ChE only.

A general biological conclusion is drawn to the effect that the cholinergic nervous system maintains the permeability of ali membranes of cells as well as of capillaries, at least as regards the cations.