Histamine Phosphate (Histamine acid phosphate) acts directly on the blood vessels to dilate arteries and capillaries mediated by both H 1- and H 2-receptors.

Histamine (10 μM) gives a larger inositol monophosphate accumulation in bovine adrenal chromaffin cells. Histamine (10 μM) stimulates the level of radioactivity into the InsP3-containing fraction in bovine adrenal chromaffin cells. Histamine (100 μM) stimulates incorporation into the InsP3-containing eluate in a less extent than for angiotensin I1 and bradykinin. [1]

Histamine phosphate (0.025 mg/kg) produces a mean increase in basilar blood flow of 145% of control in dogs. Histamine phosphate produces considerable increases in basilar blood flow as well as a decrease in femoral arterial blood pressure in dogs when injected intravenously and measured with an electromagnetic flow transducer. [2] Histamine phosphate (4 μg/kg) causes lymph flow to increase from 6.0 to 27.0 (SEM) ml/h in unanesthetized sheep. Histamine phosphate (4 μg/kg) also causes increases in lung water, pulmonary vascular resistance, arterial PCO2, pH, and hematocrit, and decreases in cardiac output and arterial PO2 in unanesthetized sheep. [3] Histamine phosphate (8.3 mg/kg/min) causes no significant change in pulmonary lymph flow (QL) or protein concentration (CL) in anesthetized open-chested dogs, however, both are increased after alloxan. Histamine phosphate (8.3 mg/kg/min) also causes no significant change in the pulmonary capillary membrane filtration coefficient (Kf) and the maximum capillary pressure (PCcritical) in anesthetized open-chested dogs. [4] Histamine phosphate (50 mg/kg) produces a pronounced rise in acid secretion but the output of pepsin remained unchanged in the unanaesthetized intact rat. Histamine phosphate (50 mg/kg) produces maximal stimulation of gastric acid secretion and is free from toxic effects in the unanaesthetized intact rat. [5]