TY - JOUR
T1 - Transient hypercapnic stress causes exaggerated and prolonged elevation of cardiac and renal interstitial norepinephrine levels in conscious hypertensive rats
AU - Sobajima, Mitsuo
AU - Nozawa, Takashi
AU - Nakadate, Teruo
AU - Shida, Takuya
AU - Ohori, Takashi
AU - Suzuki, Takayuki
AU - Matsuki, Akira
AU - Hirai, Tadakazu
AU - Inoue, Hiroshi
PY - 2011/6
Y1 - 2011/6
N2 - The responses of sympathetic nerve activity to transient stress can be exaggerated in salt-sensitive (SS), hypertensive subjects. Cardiac and renal interstitial norepinephrine (iNE) levels during and after transient hypercapnia were investigated in conscious SS rats. Dahl SS and salt-resistant (SR) 6-wk-old rats were fed a high-salt diet, and at 12 wk iNE levels in the heart and kidney were determined using microdialysis with probes inserted in the left ventricular (LV) wall and kidney. A telemetry system determined blood pressure and heart rate (HR) in separate animals. After recovery from the operation, data were collected before, during, and after exposure to normoxic 10% CO2 for 25 min under unanesthetized conditions. The plasma NE concentrations at baseline did not differ between the two strains. Both cardiac and renal iNE levels were much higher in SS rats than in SR rats at baseline as well as during hypercapnic stress. After stress, the markedly increased iNE levels of SS rats were prolonged in the LV as well as in the kidney. During hypercapnic stress, HR decreased in both SS and SR rats, while sudden increases in HR immediately after the withdrawal from stress were followed by its slower reduction in SS rats compared with SR rats. In conclusion, transient hypercapnic stress causes exaggerated and prolonged elevation of iNE levels in the heart as well as in kidneys of SS animals.
AB - The responses of sympathetic nerve activity to transient stress can be exaggerated in salt-sensitive (SS), hypertensive subjects. Cardiac and renal interstitial norepinephrine (iNE) levels during and after transient hypercapnia were investigated in conscious SS rats. Dahl SS and salt-resistant (SR) 6-wk-old rats were fed a high-salt diet, and at 12 wk iNE levels in the heart and kidney were determined using microdialysis with probes inserted in the left ventricular (LV) wall and kidney. A telemetry system determined blood pressure and heart rate (HR) in separate animals. After recovery from the operation, data were collected before, during, and after exposure to normoxic 10% CO2 for 25 min under unanesthetized conditions. The plasma NE concentrations at baseline did not differ between the two strains. Both cardiac and renal iNE levels were much higher in SS rats than in SR rats at baseline as well as during hypercapnic stress. After stress, the markedly increased iNE levels of SS rats were prolonged in the LV as well as in the kidney. During hypercapnic stress, HR decreased in both SS and SR rats, while sudden increases in HR immediately after the withdrawal from stress were followed by its slower reduction in SS rats compared with SR rats. In conclusion, transient hypercapnic stress causes exaggerated and prolonged elevation of iNE levels in the heart as well as in kidneys of SS animals.
KW - Hypercapnia
KW - Interstitial norepinephrine
KW - Salt-sensitive
UR - http://www.scopus.com/inward/record.url?scp=79958027035&partnerID=8YFLogxK
U2 - 10.1152/ajpheart.00615.2010
DO - 10.1152/ajpheart.00615.2010
M3 - 学術論文
C2 - 21421817
AN - SCOPUS:79958027035
SN - 0363-6135
VL - 300
SP - H2214-H220
JO - American Journal of Physiology - Heart and Circulatory Physiology
JF - American Journal of Physiology - Heart and Circulatory Physiology
IS - 6
ER -