[N-Alkyl-2-(5-methyl-4-imidazolyl)ethylamines. Synthesis and effect on gastric secretion]

Synthesis of some 5-methylhistamines alkylated on the amino group (form. I) together with a new method (C) of obtaining them via 5-methylhistaminol, are described. Both the agonistic and antagonistic pharmacological activities of these methylhistamines were studied in vivo on gastric secretion of different animal species (conscious dogs and cats and anaesthetized rats). The potency of the compounds, as far as the H2-receptor stimulant effect is concerned, was very remarkable in the first members of the series and decreased by increasing the degree of substitution. Independently from their "potency" some members of the series showed an "efficacy" which was actually greater than that of histamine. All the compounds tested were completely devoid of any antagonistic activity against gastric hypersecretion induced by histamine.