Catecholamine-related gene expression correlates with blood pressures in SHR.
In this study we aimed to determine whether the levels of gene expression for phenylethanolamine-N-methyltransferase (PNMT), noradrenaline transporter (NAT), alpha1A-receptor (alpha1A-R), and alpha2A-receptor (alpha2A-R) vary with resting systolic blood pressure in spontaneously hypertensive rats (SHR) compared with normotensive Wistar-Kyoto (WKY) or Sprague-Dawley (SD) rats. Sites examined included central and peripheral regions associated with the control of arterial pressure. Twenty week old SD (n=6), WKY (n=6), and SHR (n=6) were used. Systolic blood pressure was measured using tail cuff plethysmography 2 weeks before tissue extraction. RNA was isolated and reverse-transcribed into cDNA. Gene expression levels were measured, using quantitative real time PCR, relative to the expression of GAPDH. PNMT, NAT, and alpha(1A)-R mRNA expression was significantly greater in SHR tissue samples compared with normotensives. In the rostral ventrolateral medulla, PNMT mRNA in SHR was 3 times greater than that in WKY (SHR: 0.82+/-0.02%; WKY: 0.29+/-0.02%). The amount of alpha(2A)-R mRNA was significantly lower in SHR compared with normotensives. For example, the level of alpha(2A)-R mRNA in spinal cord of SHR was 3 times less than that found in WKY (SHR: 1.85+/-0.04%; WKY: 3.26+/-0.07%). PNMT, NAT, and alpha(1A)-R mRNA levels were positively correlated with systolic blood pressure in all central tissue investigated. Conversely, alpha2A-R mRNA levels in central sites were negatively correlated with systolic blood pressure. Clearly, a decrease in central alpha2A-R and an increase in alpha1A-R is consistent with the elevated blood pressure and sympathetic activity observed in SHR.
Reja
Valin
V
Hypertension and Stroke Research Laboratories, Department of Physiology, University of Sydney, Sydney, Australia.
Goodchild
Ann K
AK
Pilowsky
Paul M
PM
D000818:Animals; D001794:Blood Pressure; D002490:Central Nervous System / Q000378:metabolism; D004837:Epinephrine / Q000378:metabolism*; D005786:Gene Expression Regulation; D006973:Hypertension / Q000235:genetics* / Q000378:metabolism / Q000503:physiopathology*; D009638:Norepinephrine / Q000378:metabolism*; D050484:Norepinephrine Plasma Membrane Transport Proteins; D017933:Peripheral Nervous System / Q000378:metabolism; D010625:Phenylethanolamine N-Methyltransferase / Q000096:biosynthesis / Q000235:genetics; D012333:RNA, Messenger / Q000096:biosynthesis; D051381:Rats; D011918:Rats, Inbred SHR; D011921:Rats, Inbred WKY; D017207:Rats, Sprague-Dawley; D018340:Receptors, Adrenergic, alpha-1 / Q000096:biosynthesis / Q000235:genetics; D018341:Receptors, Adrenergic, alpha-2 / Q000096:biosynthesis / Q000235:genetics; D027981:Symporters / Q000096:biosynthesis / Q000235:genetics; D014158:Transcription, Genetic
C547715:Adra1a protein, rat; C547770:Adra2a protein, rat; D050484:Norepinephrine Plasma Membrane Transport Proteins; D012333:RNA, Messenger; D018340:Receptors, Adrenergic, alpha-1; D018341:Receptors, Adrenergic, alpha-2; C493226:Slc6a2 protein, rat; D027981:Symporters; D010625:Phenylethanolamine N-Methyltransferase; D009638:Norepinephrine; D004837:Epinephrine