Table 6.

Preclinical in vitro experiments with H₄ receptor ligands in gastrointestinal contractility and transit

Model	Species	In vitro/in vivo	Ligand	Effect	Ref
Submucous plexus neurons	Human	In vitro	4-methylhistamine	4-methylhistamine-induced excitation reduced by JNJ7777120	Breunig et al. (2007)
			JNJ7777120
Whole mount duodenum segments	Rat	In vitro	VUF8430	No effect on contractions	Pozzoli et al. (2009)
Longitudinal smooth muscle incl. myenteric plexus	Guinea pig	In vitro	Thioperamide	No effect on contractions induced by IBS supernatant	Balestra et al. (2012)
Colonic smooth muscle strips	Monkey	In vitro	4-methyl-histamine	4-methylhistamine increased contractile force	Kim et al. (2011)
Cultured small intestine interstitial cells of Cajal	Mouse	In vitro	4-methyl-histamine	No effect on pace maker potentials	Kim et al. (2013)

4-methylhistamine, H₄ receptor agonist; IBS, irritable bowel syndrome; JNJ7777120, H₄ receptor antagonist; thioperamide, H₃ and H₄ receptor antagonist; VUF8430, H₄ receptor agonist.