RESUMO
The action of PRP is characterized by the pronounced activation of the background activity (BA) of the brain spinal cord, and the degree of the activity depends on BA initial level. The typical peculiarity of Vipera raddei venom influence is the initial increase in frequency of BA with subsequent depression. A preliminary injection of PRP has a protective effect at subsequent influence of venom. In animals with hemisection the PRP increases the decreased activity of neurons on injury side. Taking into consideration the protective peculiarities of PRP in the relationship to snake venom and the possibility of the latter to stabilize and prolong the action of drugs (in the case of PRP) combined with them, it is supposed that the mentioned use of the combination in clinical practice will be perspective. The data obtained testify the PRP to be a neuroprotector against many toxic compounds formed in organism (glutamate, ceramid, beta-amyloid neurotoxisity, etc.). Investigations in this aspect are still in the process.
Assuntos
Hormônios Hipotalâmicos/farmacologia , Neurônios/efeitos dos fármacos , Fármacos Neuroprotetores/farmacologia , Peptídeos/farmacologia , Prolina/química , Venenos de Serpentes/antagonistas & inibidores , Venenos de Serpentes/toxicidade , Sequência de Aminoácidos , Animais , Hormônios Hipotalâmicos/química , Masculino , Dados de Sequência Molecular , Neurônios/patologia , Fármacos Neuroprotetores/química , Peptídeos/química , Domínios Proteicos Ricos em Prolina , Ratos , Medula Espinal/efeitos dos fármacos , Medula Espinal/patologiaRESUMO
The comparative study has been carried out on hypothalamic neurohormone (proline-rich polypeptides-PRP) and synthetic glucocorticoid dexamethasone (DEX) protective properties at the systemic (i/m) administration. Both background and evoked electrical activity (on n.ischiadicus stimulation) of single neurons in the lumbo-sacral part (laminae II-VI and VII-VIII by Rexed) and field potentials (FP) of spinal cord were recorded during acute experiments on intact spinal rats, subjected to Vipera Raddei (VR) venom intoxication, and chronic spinal cord trauma (hemisection). The action of PRP was characterized by the pronounced activation of the background activity (BA) with adaptive effect, depending on dose and initial level of BA, by results of the statistical analysis. A high effect is received from comparatively small doses. For comparison it was used strong glucocorticoid DEX, possessing single-directed but less expressed excitative action on investigated spinal cord neurons. The initial increase of BA frequency with subsequent depression was the typical symptom of venom influence. A protective effect of preliminary PRP injection is revealed on the succeeding VR venom influence. Use of PRP and DEX causes the increase of reduced activity of neurons on the injury side of animals with spinal cord hemisection. It provides the possibility of the therapeutic utilization. It was revealed considerably more expressed PRP action on neurodegenerative process connected to spinal cord injury (in comparison with DEX). The influence of hormones was compared in identical conditions of experiments on non-injured (control) and injured sides. Taking into consideration revealed protection characteristic of PRP and also the ability of snake venom to stabilize and to prolong its action combined with these preparations, the assumption is made on prospective use of the specified combination in clinical practice.
