English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Tools annual

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Tools monthly

Global: Zendy Plus monthly

Presents the access of premium content as premium feature

Premium Content

Global: Zendy Plus annual

Global: Zendy Free Plan

The role of histamine H2-receptors in AV nodal conduction was estimated in the blood-perfused AV node preparation of the dog. Histamine injected into the AV node artery caused an initial, predominant, dose-related prolongation of the AH interval, which was followed by a slight but significant shortening. Diphenhydramine, an H1-antagonist, abolished the initial prolongation, but the shortening was slightly enhanced. Cimetidine, an H2-antagonist, abolished the shortening and potentiated the initial prolongation. Dimaprit, an H2-agonist, caused only a slight, dose-related shortening of the AH interval, which was abolished by cimetidine. The shortening induced by either histamine or dimaprit was slightly suppressed, but was never abolished by atenolol, a beta-blocker, which completely abolished the noradrenaline-induced shortening. These results indicate that a positive dromotropic effect via H2-receptors exists in the canine AV node, although the main effect of histamine on AV nodal conduction is a negative one via H1-receptors.

Histamine H2-receptor mediated positive dromotropic effect in the canine atrioventricular node.