Medicines that improve the blood supply to brain tissue
This information is not intended for purposes of treatment without physician.
Description of the pharmacological group
The medicines, which improve the blood supply of brain tissues
There is a whole series of medicines, which possess general spasmolitic activity, which cause vasodilation and improving blood circulation in different organs and tissues, which favorably affect the blood supply of the brain, they increase the guarantee with its oxygen, strengthen in it metabolic processes, in consequence of which widely they adapt during the disturbances of cerebral blood circulation.
The brain is the unique organ, whose basic vascular pond is located not inside, but on its surface, and it is the system of the vessels of pia mater, from which will move away the radial vessels, that supply blood brain tissue. Besides this on the channel of cerebral vessels are located numerous bends - “siphons”, which smooth out pressure differentials. This construction of the vascular channel of the brain makes it possible to level pressure differentials and pulsatory nature of blood flow for guaranteeing a constant inflow of the blood to the neurons, independent of the functional state of organism and position of body. Since brain tissues are extremely sensitive to the shortage of oxygen, the volume velocity of cerebral blood flow is very great and in adult person is 750 ml/min (13-15% of heart emission). If one considers that the mass of the brain is approximately 1 400 g, it is not difficult to calculate, which per minute to each gram of brain tissue enters more than 0.5 ml of the blood.
The influence of vegetative nervous system on the tone of cerebral vessels is insignificant. In essence their tone is determined by the complex system of the myogenic and metabolic mechanisms, whose nature up to now is not finally clear. However, it is known that the stress of the dioxide of carbon in capillaries and brain tissues is the important metabolic factor, which participates in the regulation of the tone of the vessels of the brain. It is proven that an increase in this stress in the brain tissue 2 times entails a approximately two-fold increase in the volume velocity of cerebral blood flow.
Unfortunately, at present are not created the medicines, which selectively influence the cerebral blood circulation. However, there is a sufficiently large number of medicines with the myotropic spasmolitic activity, capable of to one extent or another improving blood supply and, therefore, the metabolism of brain tissues; therefore given preparations widely use in the clinical practice for treating the disturbances of cerebral blood circulation. As a rule, they not only act on cerebral blood circulation, but they to one extent or another influence the metabolism of nerve cells, increasing their stability to ischemia and/or hypoxias, improve the rheological properties of the blood, i.e., besides the action on the tone of the vessels of the brain they render the specific neuroprotective action.
The medicines, which improve cerebral blood circulation, can be classified as follows:
- the methylxanthine derivatives - euphyllin (aminophylline), pentoxifylline of others;
- the blockers of calcium channels - nimodipine, of flunarizin, cinnarizine and others;
- α- adrenoblockers - the derivatives of the alkaloids of ergot - dihydroergotamine, nicergoline and other;
- the derivatives of nicotinic acid - xantinol nicotinate, nikoshpan and other;
- the derivatives of glycosides of periwinkle - vinpocetine;
- the derivatives of GABA (gamma-aminobutyric acid) - aminalon, picamilone and others;
- the medicines of different groups - bendazol and of others;
- the combined medicine - instenon.
The preparation of instenon includes in its composition three components: hexobendine, etamivan and ethophilline.
Hexobendine possesses the wide spectrum of pharmacological effects, which includes the neurometabolic, vasodilator and membrane stabilizing action. Against the background the method of preparation are stabilized the mechanisms of the autoregulation of cerebral (cerebral) blood flow, the processes of synaptic transfer are normalized, transport and absorption by the brain tissues of glucose increases.
Etamivan in the chemical structure and the pharmacological activity is close to the analytical medicine to nikethamide (sin. cordiamine). Preparation excites the vasomotor and respiratory centers of CNS, it renders the expressed activating influence on the limbic system and the reticular formation of the stem of brain, facilitates interneuronal interaction of the cerebral cortex and subcortical structures.
Ethophilline in the chemical structure and the pharmacological activity is close to selective A1-adenosine blockers, derivative of methylxanthin to preparation theophylline. Preparation has the stimulating effect on vasomotor center CNS, improves the pumping function of heart, which entails an increase in the volume velocity of blood flow, including on the vessels of brain, which is in turn accompanied by the lift of the perfusion pressure of the blood and, as a consequence of this, by an improvement in the blood supply of the ischematized tissues of brain. Besides this there are data about the fact that the preparation improves microcirculation in the tissues of brain.
Thus, the combined preparation of instenon renders on the brain tissue the complex multifactor action, as a result which is improved blood flow on by the vessel of the brain, including microcirculation, neuromediator and metabolic processes are stabilized, rises the stability of cellular membranes to hypoxia and ischemia, i.e., preparation it possesses the expressed cerebrovascular protector action.
In the clinical practice of instenon they use for treating of ischemic stroke, residual phenomena after the previous stroke, discirculatory and post-traumatic encephalopathy and other clinical manifestations of cerebrovascular insufficiency. However, one should remember about the fact that instenon is contrasted at the increased intracranial pressure, hemorrhagic stroke and eclampsia.
Preparation is assigned per os, it is intravenous and it is intramuscular.