has part has part has_part characteristic of has modifier histamine abnormal histamine level increased histamine level 2018-09-14T08:54:20Z increase in the amount of histamine, an amine derived from the decarboxylation of histidine that is involved in local immune responses, in regulating physiological function in the gut, and that acts as a neurotransmitter for the brain, spinal cord, and uterus; histamine is involved in the inflammatory response and has a central role as a mediator of itching MPheno.ontology MP:0030755 abnormal increased amount