Cardiovascular effects of dopamine in developing swine

Area of Science:

• Cardiovascular Physiology
• Neonatal Physiology

Background:

• Dopamine is a critical neurotransmitter and hormone.
• Its effects on cardiovascular function vary with age and dosage.

Purpose of the Study:

• To investigate the effects of dopamine on cardiac function and peripheral blood flow in developing and mature swine.
• To determine the age-dependent development of dopamine's vascular responses.

Main Methods:

• Measurements of cardiac function and peripheral blood flow.
• Intravenous injections of dopamine (2-25 micrograms/kg) in anesthetized swine.
• Assessment of responses in developing (younger than 1 month) and mature animals.

Main Results:

• A positive inotropic effect of dopamine was observed across all age groups.
• Renal vasoconstriction occurred with low dopamine doses in animals younger than 1 month.
• Femoral vasoconstriction was noted in animals younger than 2 weeks, unless alpha-adrenergic receptors were blocked.

Conclusions:

• Dopamine exerts a positive inotropic effect even in the youngest swine.
• Dopamine-induced vasoconstriction develops earlier in the femoral circulation than in the renal circulation.
• The development of vasodilator responses to dopamine is age-dependent.