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Cocaine administration induces human splenic constriction and altered hematologic parameters
M J Kaufman1, A J Siegel, J H Mendelson
1Brain Imaging Center, McLean Hospital, Harvard Medical School, Belmont, Massachusetts 02478, USA. kaufman@mclean.org
Journal of Applied Physiology (Bethesda, Md. : 1985)
|November 6, 1998
Summary
Cocaine use temporarily constricts the spleen in men, leading to increased red blood cell counts. This spleen constriction may help maintain oxygen delivery during high demand.
Area of Science:
- Pharmacology
- Hematology
- Physiology
Background:
- Cocaine is a known vasoconstrictor.
- Previous studies indicate cocaine alters blood parameters like hemoglobin and hematocrit.
- The effect of cocaine on spleen volume in humans is not well understood.
Purpose of the Study:
- To investigate if cocaine administration causes splenic constriction in men.
- To determine if changes in spleen volume correlate with alterations in hematologic parameters.
- To explore the potential physiological implications of cocaine-induced spleen changes.
Main Methods:
- Five healthy male subjects with occasional cocaine use participated.
- Spleen volume was measured using magnetic resonance imaging before and after cocaine administration (0.4 mg/kg).
- Hematologic parameters (hemoglobin, hematocrit, red blood cell, white blood cell, and platelet counts) were analyzed.
Main Results:
- Cocaine administration caused a significant 20% reduction in spleen volume within 10 minutes.
- Spleen volume returned to baseline levels within 35 minutes, indicating a transient effect.
- Cocaine increased hemoglobin, hematocrit, and red blood cell counts, but not white blood cell or platelet counts.
Conclusions:
- Cocaine induces transient splenic constriction in humans.
- This splenic constriction is temporally associated with increased red blood cell counts.
- These changes may enhance tissue oxygenation during periods of increased oxygen demand or vascular resistance.