Genetic isolation of a blood pressure quantitative trait locus on chromosome 2 in the spontaneously hypertensive rat

Objectives Total genome scans of genetically segregating populations derive d from the spontaneously hypertensive rat (SHR) and other rat models of hyp ertension have suggested the presence of quantitative trait loci (QTL) regu lating blood pressure and cardiac mass on multiple chromosomes, including c hromosome 2, The objective of the current study was to directly test for th e presence of a blood pressure QTL on rat chromosome 2. Design A new congenic strain was derived by replacing a segment of chromoso me 2 in the SHR between D2Rat171 and D2Arb24 with the corresponding chromos ome segment from the normotensive Brown Norway rat. Arterial pressures were directly monitored in conscious rats by radiotelemetry. Results We found that the SHR congenic strain (SHR-2) carrying a segment of chromosome 2 from the Brown Norway rat had significantly lower systolic an d diastolic blood pressures than the SHR progenitor strain. The attenuation of hypertension in the SHR-P congenic strain versus the SHR progenitor str ain was accompanied by significant amelioration of cardiac hypertrophy. Conclusions These findings demonstrate that gene(s) with major effects on b lood pressure exist in the differential segment of chromosome 2 trapped wit hin the new SHR.BN congenic strain.