ABSTRACT
Reactivity of rat mesenterial microvessels was studied during mesenterial shock. The development of the shock was discovered to involve two phases in the changes of microvascular reactivity. The sensitivity of microvessels to adrenaline was increased at the beginning of the shock whereupon it started descending. This phenomenon evidences that vasodilatation occurring at the late stages of the shock development is determined not only by a reduction in the concentration of endogenous adrenaline and noradrenaline but also by a decrease in the sensitivity of microvessels to these agents. The data obtained make it possible to explain the mechanism of steady vasodilatation in response to injection of exogenous adrenaline and noradrenaline, which is seen at the late stages of mesenterial shock.
Subject(s)
Mesentery/blood supply , Shock/physiopathology , Animals , Dose-Response Relationship, Drug , Epinephrine/pharmacology , Ligation , Male , Mesenteric Arteries/physiology , Microcirculation/drug effects , Microcirculation/physiopathology , Rats , Shock/etiology , Time FactorsABSTRACT
Microcirculatory disturbances in pia mater are followed by change in oxygen tension in the brain cortex. Immediately after bleeding initial decrease of oxygen tension by 60-70% of the basal level was observed. This decrease was induced by initial vasoconstriction and brain cortex hypoxia. After compensation of blood circulation supervened and the cortical blood flow was set to a lower level (30-40 minutes after the decrease), there occurred a phase of oxygen level stabilization. The oxygen tension remained unchanged for a long time and decreased very slowly. More rapid fall of oxygen tension was noticed only at the end of the fourth hour when circulation decompensation set in.
Subject(s)
Cerebral Cortex/physiopathology , Oxygen Consumption , Shock, Hemorrhagic/physiopathology , Animals , Male , Microcirculation/physiopathology , Partial Pressure , Rats , Rats, Inbred Strains , Time FactorsSubject(s)
Gastrectomy , Intestine, Small/blood supply , Neuroleptanalgesia , Acid-Base Equilibrium/drug effects , Animals , Blood Viscosity/drug effects , Hemodynamics/drug effects , Male , Microcirculation/drug effects , Pentobarbital , Rats , Rats, Inbred Strains , Splanchnic Circulation/drug effectsABSTRACT
The role of arachidonic acid (3--5 mg/kg animal body weight) in the intravascular red cell aggregation was studied on rats by intravital microscopy. It has been established that intravenous injection of arachidonic acid leads to aggregation and red cell hemolysis, and animals' death. Preliminary injection of acetylsalicylic acid or pentoxyphylline prevents the initiation of aggregation and lysis of red cells but does not avert the animals' death because of arachidonic acid. It is concluded that arachidonic acid plays an important role in aggregation and lysis of red cells. It is recommended that reasons for animals' death because of arachidonic acid in the absence of microcirculatory disorders be studied.
Subject(s)
Arachidonic Acids/antagonists & inhibitors , Aspirin/pharmacology , Erythrocyte Aggregation/drug effects , Pentoxifylline/pharmacology , Theobromine/analogs & derivatives , Animals , Arachidonic Acids/poisoning , Hemolysis/drug effects , In Vitro Techniques , RatsABSTRACT
The role of proteolytic enzymes in intravascular aggregation of red cells was studied in experiments on rats by intravital microscopy. Intravenous injection of trypsin (40--50 mg/kg) combined with heparin (1000 units/kg) produces marked intravascular aggregation of red cells. Preliminary infusion of pentoxyphyllin (20 mg/kg) or acetylsalicylic acid (100 mg/kg) blocked this process. A conclusion is made about an important role of proteolytic enzymes play in the development of microcirculatory disorders. A possible mechanism of the aggregating action of trypsin and approaches to its correction are discussed.
Subject(s)
Erythrocyte Aggregation/drug effects , Trypsin/pharmacology , Animals , Aspirin/pharmacology , Heparin/pharmacology , Pentoxifylline/pharmacology , RatsABSTRACT
In experiments on parabiotic rats with crossed circulation and separate innervation mechanical or burn trauma of one of the partners was followed by shock-like condition of the other one, and by microcirculatory changes in the mesentery typical of burn or traumatic shock. It shows that in burn shock, as well as in traumatic one, the detected changes in microcirculation are due to humoral, but not to neural factors.