The role of sympathetic reinnervation of kidney grafts for the development of renal post-transplantation hypertension was investigated. F1-hybrids (F1H) obtained from crossing spontaneously hypertensive (SHR) and Wistar-Kyoto rats were transplanted with an SHR kidney and bilaterally nephrectomized. Seven (n = 7) and 42 days after transplantation (n = 9), transplanted kidneys were removed and renal norepinephrine concentrations were determined. In addition, mean arterial pressure (MAP) was measured in conscious bilaterally nephrectomized recipients of an SHR (n = 9) or F1H kidney (n = 8) 6 weeks after transplantation. Renal norepinephrine concentrations (ng/g wet kidney weight) decreased dramatically from 348.3 +/- 31.7 ng/g before (n = 7) to 9.9 +/- 2.5 ng/g at 7 days and 6.5 +/- 1.1 ng/g at 42 days after transplantation, indicating that there was no substantial sympathetic reinnervation of the grafts throughout the observation period. Despite the lack of reinnervation of the grafts, recipients of an SHR kidney but not recipients of an F1H kidney developed post-transplantation hypertension (MAP 172 +/- 4 mmHg versus 124 +/- 3 mmHg P < 0.001) within 6 weeks after transplantation. We conclude that post-transplantation hypertension in recipients of an SHR kidney does not depend on sympathetic reinnervation of the graft.