On the Degranulation of Mesenteric Mast Cells Caused by Antihistamine in Albino Rats: Effects of Various Dosages of Antihistamine

ABSTRACT

Degranulation of the mast cell has been reported by the injection of histamine liberators and other chemical agents. Chlorpheniramine maleate (1.2mg./kg. and 0.3mg./kg. comprising 1/74and 1/290 of LD50 respectively), which is an antihistamine agent, in physiological saline solution for intravenous injection and in Tyrode solution for intraperitoneal injection were given in single dose. The mesenteric mast cells stained in Pugh solution, as applied by Lee (1968), were counted according to the classification of An (1964) in 4 types; the typical normal mast cell, the Grade I type of mast cell, the Grade II type of mast cell and the Grade III type of mast cell. In the experimental rats given 1.2mg./kg. of chlorpheniramine intravenously, more mesenteric mast cells were s1ightly degranulated than those cells of the rats given 0.3mg./kg. of chlorpheniramine and the control rats. In the experimental rats given 1.2mg./kg. and 0.3 mg./kg. of chlorpheniramine intraperitoneally, more mesenteric mast cells were slightly degranulated than those cells of the control rats. However, in this intraperitoneal study the degree, or severity, of degranulation of the mesenteric mast cell was not in direct proportion to the dosage of this antihistamine. Consequently it is deduced that the experimental dosage of the antihistamine chlorpheniramine maleate, applied 1/74 and l/290 of LD50, caused an evient degranulation of mesenteric mast cells of the albino rats associated with probable histamine liberation.