HISTOCHEMICAL AND ELECTRON MICROSCOPIC OBSERVATIONS OF POLYGLUCOSE SYNTHESIZED BY ENZYMES IN THE SINO-ATRIAL NODAL CELL OF RABBITS TREATED WITH β-STIMULATING AND β-BLOCKING AGENTS

Abstract

Phosphorylase activity was histochemically stimulated in the heart conduction system of rabbits by pretreatment with isoproterenol, but not in the case of the use of propranolol.
With observation under the electron microscope, the new polyglucose particles which were histochemically synthesized from glucose 1-phosphate by the phosphorylase-branching glycosyltransferase system appeared to be deposited more abundantly than usual in the intracytoplasmic matrix of S-A nodal cells and in the nuclear matrix after the isoproterenol administration, while this was not the case with propranolol-treatment. These particles were more abundant and larger in size than native glycogen particles.