Physiology - Research Publications
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ItemNo Preview AvailableLow affinity nerve growth factor receptor gene co-segregates with decreased bodyweight and increased left ventricular weight in spontaneously hypertensive ratsKapuscinski, MK ; Nemoto, K ; Ueyama, T ; Charchar, F ; Kageyama, H ; Fukumachi, K ; Sekimoto, M ; Senba, E ; Tomita, T ; Tomita, I ; Harrap, SB (WILEY, 1996-06-01)1. The sympathetic nervous system influences the cardiovascular and hormonal systems and sympathetic innervation is dependent on nerve growth factor (NGF). The NGF gene is linked genetically to high blood pressure in the spontaneously hypertensive rat (SHR) and there exists a mutation in the SHR low affinity NGF receptor (LNGFR) gene. 2. To determine whether the LNGFR mutation was linked genetically with cardiovascular phenotypes we studied an F2 population derived from SHR and normotensive Donryu (DRY) rats. 3. Mean arterial pressure (MAP), left ventricular mass (LVM) and related phenotypes were measured in 127 20 week old male F2 rats and correlated with the inheritance of the SHR mutation (S) and/or the DRY allele (D) of the LNGFR. 4. Analysis of variance revealed that the S mutation was associated with a significantly lower bodyweight in F2 rats (P < 0.0001). 5. The S mutation was associated with a significant (P < 0.007) increase in LVM:bodyweight ratio, but not with differences in right ventricular or kidney weights corrected for bodyweight. We found no association between MAP and LNGFR alleles or genotypes. 6. These results suggest that the mutation in the signal peptide of LNGFR may serve as a useful marker for the analysis of genetic factor(s) involved in the differential determination of body size and heart weight.
ItemNo Preview AvailableNerve growth factor gene and hypertension in spontaneously hypertensive ratsKapuscinski, M ; Charchar, F ; Innes, B ; Mitchell, GA ; Norman, TL ; Harrap, SB (LIPPINCOTT WILLIAMS & WILKINS, 1996-02-01)OBJECTIVE: High blood pressure in spontaneously hypertensive rat (SHR) is associated with increased sympathetic innervation of key tissues, possibly as the result of increased nerve growth factor (NGF). The aim of this study was to test for genetic linkage of the NGF gene to high blood pressure. DESIGN: We studied NGF gene expression in young SHR and examined linkage of the NGF locus to mean arterial pressure in genetically segregating crosses of SHR and normotensive Donryu (DRY) rats. METHODS: NGF mRNA was measured by Northern blot, and a restriction fragment length polymorphism of the NGF gene revealed after digestion with the NsiI restriction enzyme was used to study inheritance. RESULTS: Levels of NGF mRNA were detected easily in the kidneys of 2-, 4- and 10-week-old SHR but not in age-matched DRY rats. In an F2 population, the blood pressure of rats homozygous for the DRY NGF allele was 6 mmHg less than in heterozygotes and 8 mmHg less than in rats homozygous for the SHR NGF allele (analysis of variance, P < 0.004). In backcross rats the blood pressure of NGF heterozygotes was not significantly different from that of SHR homozygotes. CONCLUSION: These results indicate differences in renal NGF mRNA in SHR during the development of hypertension and suggest that a genetic locus in or near the NGF gene contributes in a Mendelian dominant pattern to a significant increment in blood pressure in SHR.