Effects of preweaning doxazosin treatment on adult pressure in the spontaneously hypertensive rat

1. The neonatal/preweaning period appears to represent a critical period of involvement of the sympathetic nervous system in the development of hypertension in spontaneously hypertensive rats (SHR). 2. We tested whether α₁-adrenoceptor-mediated effects during the preweaning period are involved in the development of hypertension in the adult SHR. 3. Male SHR were treated with the α₁-adrenoceptor antagonist doxazosin (10 mg/kg per day, s.c.) from postnatal day 1 to 21 inclusive. Direct conscious blood pressure and heart rate were measured via the caudal artery at 12 weeks of age. 4. Preweaning treatment with doxazosin had no significant effect on mean arterial blood pressure or heart rate in male SHR at 12 weeks of age. 5. These findings do not support the involvement of α ₁-adrenoceptor-mediated effects during the preweaning period in the development of hypertension in adult SHR.