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Spontaneous hypertension in the neonatal rat. A review
Insights
Early hypertension in spontaneously hypertensive rats (SHR) shows significant cardiovascular changes even before the prehypertensive stage. These findings challenge the use of this early period as a solely control phase for hypertension research.
Area of Science:
- Cardiovascular Physiology
- Hypertension Research
- Animal Models of Disease
Background:
- The 'prehypertensive stage' in spontaneously hypertensive rats (SHR) was initially defined as a control period before systolic pressure exceeded 150 mm Hg.
- However, significant cardiovascular alterations are evident much earlier, even by the weanling stage in SHR.
Purpose of the Study:
- To review recent literature on the early developmental stages of hypertension in SHR.
- To highlight cardiovascular changes occurring before the traditional prehypertensive period.
Main Methods:
- Literature review of studies on spontaneously hypertensive rats (SHR).
- Analysis of research focusing on early postnatal development and cardiovascular parameters.
Main Results:
- Early onset of pressure rise in SHR.
- Evidence of arterial and ventricular hypertrophy in weanling SHR.
- Increased sympathetic vasomotor tone observed in early postnatal SHR.
Conclusions:
- The early postnatal period in SHR is characterized by significant hypertensive changes, not merely a control phase.
- Cardiovascular alterations occur prior to the established 'prehypertensive stage'.
Abstract:
'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.