ABSTRACT
In this study we investigated a motor-neuronal functional state based on H- and M-responses from m. quadratus plantae in dogs before and after experimental spinal cord contusion with and without following local intraoperative hypothermia. H- and M-responses from m. quadratus plantae were recorded during stimulation of the tibial nerve and results were compared between the groups. Our results demonstrate that local hypothermia applied after spinal cord contusion reduces amplitude of both M- and H-responses and also H(max)/M(max) ratio that may indicate depression of motorneurons excitability. After spinal cord contusion without following hypothermia the excitability of the spinal motorneurons during post-traumatic period, in opposite, was significantly increased. These results support a conclusion that intraoperative hypothermia after spinal cord contusion can delay development of functional excitability of the motoneurons and protect from further changes in H- and M-responses.
Subject(s)
Hypothermia, Induced , Neural Conduction , Spinal Cord Injuries/physiopathology , Tibial Nerve/physiopathology , Animals , Dogs , Motor Neurons/pathology , Spinal Cord Injuries/pathology , Tibial Nerve/pathology , Transcutaneous Electric Nerve StimulationABSTRACT
By electron paramagnetic resonance method analyzed the production of nitric oxide (NO) in atrias and ventricles of the rat's heart, spinal cord and liver of rats after the contained in conditions of hypokinesia during 30, 60 and 90 days. It was discovered that the regime of hypokinesia leads to increase NO production in all the investigated tissues, and the largest increases were observed in 30-day hypokinesia.
Subject(s)
Heart Atria/metabolism , Heart Ventricles/metabolism , Immobilization , Liver/metabolism , Nitric Oxide/biosynthesis , Spinal Cord/metabolism , Adaptation, Physiological , Animals , Animals, Outbred Strains , Electron Spin Resonance Spectroscopy , Rats , Time FactorsABSTRACT
By the method of EPR spectroscopy we studied the intensity of nitric oxide (NO) production after modeling of hypokinesia in rats (limitation of moving activity) through analyses of the amount of NO-containing paramagnetic complexes in tissues of heart and liver. Experimental animals were kept during 60 day protracted hypokinesia. NO amount was assessed by the intensity of EPR spectra of complex (DEDTC)2-Fe(2+)-NO. It was established that after 60 day hypokinesia the 2-3 fold increase of NO quantity occured in heart and liver tissues. The application of a nonspecific inhibitor of NO-synthases, L-NAME, in suspended rats led to a decreased NO quantity up to the value more lower than in control. The obtained results show that the main contribution to the increase in the intensity of NO production during hypokinesia belongs to the fermentative pathway of NO production and the formation of NO by nitrite-reductase activity is not enhanced during hypokinesia.
Subject(s)
Electron Spin Resonance Spectroscopy , Myocardium/metabolism , Nitric Oxide/biosynthesis , Animals , Hypokinesia/metabolism , Hypokinesia/physiopathology , Liver/metabolism , Metabolic Networks and Pathways/drug effects , NG-Nitroarginine Methyl Ester/administration & dosage , Nitric Oxide/metabolism , Nitric Oxide Synthase Type II/antagonists & inhibitors , Nitric Oxide Synthase Type II/metabolism , RatsABSTRACT
Nitric oxide production in heart tissues of rats of different age in the norm and after pharmacological sympathectomy was studied by electron spin resonance spin-trapping. Rats at the age of 14, 21, 70, and 100 days were used in the experiment. The concentration of nitric oxide produced in rat heart tissues proved to considerably decrease during ontogeny. Pharmacological sympathectomy notably decreased nitric oxide production in the heart in 14- and 21-day-old rats: the nitric oxide concentration in the spin trap as well as the level of R and T conformers of hemoglobin nitrosyl complexes decreased. In 70-day-old rats, pharmacological sympathectomy had no notable effect on the level of nitric oxide-containing paramagnetic complexes.
Subject(s)
Aging/metabolism , Myocardium/metabolism , Nitric Oxide/metabolism , Animals , Rats , Sympathectomy, Chemical/methodsABSTRACT
Reflex excitability of spinal centers of hand muscles was examined in normal subjects and patients with traumatic lesion of forearm nerves. Central and peripheral muscle responses were evoked by stimulation of homonymous and heteronymous nerves. Patients with median and/or ulnar nerve lesion showed the heteronymous abductor pollicis brevis and abductor digit minimi H-responses. The cause of appearance of heteronymous responses is supposed to be actualization of latent heteronymous monosynaptic connections following traumatic lesion and afferent deprivation. It seems obvious that activation of heteronymous pathways corresponds to the process in afferent system known as "revitalization" of median-to-ulnar anastomoses after damage.
