Spontaneous hypertension in the neonatal rat. A review.

'Prehypertensive stage' was originally used to designate the initial developmental stage of hypertension in spontaneously hypertensive rats (SHR). The period covered the first 6-7 weeks of age, before the systolic pressure exceeded 150 mm Hg and many investigations have used this stage as a control period with which to compare later hypertensive changes. Significant hypertensive changes occur early in this period however, and numerous studies have revealed the extent to which cardiovascular alterations have already occurred by the weanling stage. This review summarizes much of the recent literature relating to the onset of the pressure rise, arterial and ventricular hypertrophy and increased sympathetic vasomotor effects in the early postnatal stage in SHR.