[Reactive changes in adrenergic innervation of the cerebral arteries after activation of the cholinergic mechanisms]

Magistral arteries of the brain and pia mater have been studied in cats 24-72 h after administration of the cholinesterase inhibitor (phosphacol, 600 mcg/kg). Cholinesterase activity in blood has been checked by means of the potentiometric titration method, and acetylcholinesterase (AChE) content in varicosities of the perivascular nervous fibers--cytophotometrically in preparations treated after Karnovsky--Roots histochemical method. Cholinesterase activity of blood homogenates in test animals is 42 +/- 10%, and acetylcholinesterase content in varicosities of the perivascular nervous fibers--23.5 +/- 2.3% in comparison to the norm. Catecholamines in adrenergic nervous elements are revealed treating them with glyoxylic acid. Distribution density (DD) of histochemically active nervous elements is determined, as well as their specific content of the mediator according to luminescent intensity (LI) of varicosities of nervous fibers. The data obtained in intact animals serve as the control. In the experiment DD and LI reach 127 +/- 9% and 154 +/- 15%, respectively, as compared to the control. Signs of the adrenergic nervous apparatus activation in the experiment reflect a compensatory reaction in response to increase of dilatatory cholinergic influences to vessels under conditions of AChE activity.