Impaired myogenic response and autoregulation of cerebral blood flow is rescued in CYP4A1 transgenic Dahl salt-sensitive rat.

Abstract

We have reported that a reduction in renal production of 20-HETE contributes to development of hypertension in Dahl salt-sensitive (SS) rats. The present study examined whether 20-HETE production is also reduced in the cerebral vasculature of SS rats and whether this impairs the myogenic response and autoregulation of cerebral blood flow (CBF). The production of 20-HETE, the myogenic response of middle cerebral arteries (MCA), and autoregulation of CBF were compared in SS, SS-5(BN) rats and a newly generated CYP4A1 transgenic rat. 20-HETE production was 6-fold higher in cerebral arteries of CYP4A1 and SS-5(BN) than in SS rats. The diameter of the MCA decreased to 70 ± 3% to 65 ± 6% in CYP4A1 and SS-5(BN) rats when pressure was increased from 40 to 140 mmHg. In contrast, the myogenic response of MCA isolated from SS rats did not constrict. Administration of a 20-HETE synthesis inhibitor, HET0016, abolished the myogenic response of MCA in CYP4A1 and SS-5(BN) rats but had no effect in SS rats. Autoregulation of CBF was impaired in SS rats compared with CYP4A1 and SS-5(BN) rats. Blood-brain barrier leakage was 5-fold higher in the brain of SS rats than in SS-5(BN) and SS.CYP4A1 rats. These findings indicate that a genetic deficiency in the formation of 20-HETE contributes to an impaired myogenic response in MCA and autoregulation of CBF in SS rats and this may contribute to vascular remodeling and cerebral injury following the onset of hypertension.

• Authors: Fan Fan, Aron M Geurts, Sydney R Murphy, Mallikarjuna R Pabbidi, Howard J Jacob, Richard J Roman
• Journal: American journal of physiology. Regulatory, integrative and comparative physiology (Am J Physiol Regul Integr Comp Physiol) Vol. 308 Issue 5 Pg. R379-90 (Mar 01 2015) ISSN: 1522-1490 [Electronic] United States
• PMID: 25540098 (Publication Type: Journal Article, Research Support, N.I.H., Extramural, Research Support, Non-U.S. Gov't)
• Copyright: Copyright © 2015 the American Physiological Society.

Chemical References

• Hydroxyeicosatetraenoic Acids
• Sodium Chloride, Dietary
• 20-hydroxy-5,8,11,14-eicosatetraenoic acid
• Cytochrome P-450 CYP4A
• Transposases
• sleeping beauty transposase, human

Topics

• Animals
• Arterial Pressure
• Blood-Brain Barrier (metabolism)
• Capillary Permeability
• Cerebrovascular Circulation
• Cytochrome P-450 CYP4A (genetics, metabolism)
• Disease Models, Animal
• Genotype
• Homeostasis
• Hydroxyeicosatetraenoic Acids (metabolism)
• Hypertension (enzymology, genetics, physiopathology)
• Middle Cerebral Artery (enzymology, physiopathology)
• Phenotype
• Rats, Inbred Dahl
• Rats, Inbred Lew
• Rats, Transgenic
• Sodium Chloride, Dietary
• Transposases (genetics)
• Vascular Remodeling
• Vasoconstriction