Increased nerve growth factor levels in spontaneously hypertensive rats.
OBJECTIVE
Increased sympathetic innervation has been reported in spontaneously hypertensive rats (SHR); however, the precise mechanisms involved are not yet clear. Nerve growth factor (NGF), a neurotrophic peptide in peripheral sympathetic neurons, is believed to contribute to this phenomenon.


METHODS
We measured the content of NGF in SHR and control Wistar-Kyoto (WKY) rats during development. Mesenteric artery, spleen, heart and sciatic nerve were isolated and homogenized. NGF content in the supernatant fractions was measured using a highly sensitive and specific two-site enzyme immunoassay.


RESULTS
At 3 weeks of age, SHR had a greater NGF content in the spleen, the sciatic nerve and the mesenteric artery than WKY rats. However, these differences disappeared completely at 12 weeks of age. Cardiac NGF content was slightly lower in 3-week-old SHR and, conversely, higher in 12-week-old SHR than in age-matched WKY rats.


CONCLUSIONS
These findings suggest that, except for the heart, the SHR tissues observed overproduce NGF at a young age, leading to enhancement of peripheral sympathetic nervous system activity and the production of vasoconstrictive catecholamines.
Ueyama
T
T
Department of Medicine, Wakayama Medical College, Japan.
Hamada
M
M
Hano
T
T
Nishio
I
I
Masuyama
Y
Y
Furukawa
S
S
D000375:Aging / Q000378:metabolism; D000818:Animals; D006346:Heart Septum / Q000737:chemistry; D006973:Hypertension / Q000209:etiology / Q000378:metabolism*; D007124:Immunoenzyme Techniques; D008638:Mesenteric Arteries / Q000737:chemistry; D009414:Nerve Growth Factors / Q000032:analysis*; D051381:Rats; D011918:Rats, Inbred SHR / Q000502:physiology*; D011921:Rats, Inbred WKY; D012584:Sciatic Nerve / Q000737:chemistry; D013154:Spleen / Q000737:chemistry
D009414:Nerve Growth Factors