Concentration effect relationships of infused histamine in normal volunteers.
Level 4 - case-series / case-control
Uncontrolled experimental human laboratory series
PubMed 7080947 · doi:10.1007/BF01965099
What was done
Histamine was infused in six normal volunteers at stepwise increasing rates (16, 32, 64, and 96 ng/kg/min at 5-minute intervals), followed by 128 ng/kg/min for 45 minutes. Hemodynamic variables (heart rate, diastolic blood pressure), skin temperature, salivary flow, plasma catecholamines (adrenaline, noradrenaline), and plasma histamine concentrations and clearance kinetics were measured.
What was found
At the highest infusion rate (128 ng/kg/min): - Heart rate increased by 15.6 ± 5.7 beats/min. - Diastolic blood pressure decreased by 8.8 ± e.2 mmHg. - Skin temperature increased by 1.2 ± 0.3 °C. - Mean plasma histamine increased from 0.20 ± 0.03 ng/ml at baseline to 1.97 ± 0.25 ng/ml. - The threshold infusion rate for physiological effects was 64–96 ng/kg/min (plasma concentration 0.77–0.97 ng/ml). - Salivary flow increased by 21% at 30 min (P = 0.05). - Plasma adrenaline increased by 132%, with no change in noradrenaline. - Heart rate recovery half-time was 82 seconds, plasma histamine half-life was 102 seconds, and plasma clearance was 6.1 ± 0.2 l/min (83 ml/kg/min).
Why it matters
This study defines physiological effect thresholds and rapid clearance kinetics for infused histamine in humans, suggesting that previously reported high endogenous plasma histamine values in the literature may be inaccurate.
Limits
The study had a very small sample size (n = 6) and lacked a separate control or placebo arm. Exact participant characteristics and demographics were not reported in the abstract.
Cited by
- partial In a human study where participants were injected with liquid histamine, increasing histamine within the upper-normal range caused increased heart rate and anxiety as the first symptoms.