A Late Response on the Cholinergic Neurotransmitter System in Acute Massive Blood Loss

Abstract

Objective: to study the impact of acute massive blood loss on the properties of muscarinic cholinergic receptors and catalytic parameters of cerebral acetylcholinesterase in albino rats in the late resuscitative periods.Materials and methods. Experiments were made on anesthetized non-inbred overanxious male rats exposed to 2-hour arterial hypotension (mean blood pressure 40—45 mm Hg). M-cholinergic receptor binding to the radioligand H3-quinuclidinyl benzilate was estimated by the method of Yamamura and Snyder (1974) and the catalytic properties of rat cerebral acetylcholinesterase on postresusci-tative day 40 were determined by the colorimetric technique (Ellman et al. 1961).Results. A response of m-cholinergic receptors to impaired cholinergic inflow has been found to appear as the higher efficiency of their performance, by increasing affinity and to be aimed at providing the normal functioning of synapses in cholinergic mediation deficiency.Conclusion. The findings suggest that this late hypercompensation of the cholinergic system in the postresuscitative period is excessive to the brain nerve cells of the rats experienced massive blood loss and resuscitation and, by causing nerve tissue structural changes, may result in the occurrence of new pathological processes.

Keywords

• hypovolemic hypotension
• blood reinfusion
• late postresuscitative period
• m-cholinergic receptors
• acetylcholinesterase
• brain tissue
• efficiency of synaptic performance