Bolus intravenous injection of obestatin does not change blood pressure level of spontaneously hypertensive rat.
Ghrelin, an endogenous ligand for the GH secretagogue receptor, has been shown to decrease arterial pressure. Obestatin, a sibling of ghrelin derived from preproghrelin, opposes several physiological actions of ghrelin. The aim of this study was to determine the effects of bolus intravenous injection of obestatin on blood pressure in spontaneously hypertensive rats. Three different dosages of obestatin (10, 50, and 100 microg/kg) and one dosage of ghrelin (10 microg/kg) were applied. The mean arterial pressure and heart period were continuously recorded for 30 min after injection of drugs. Baroreflex sensitivity was also investigated. In this study, we first demonstrated that intravenous injection of obestatin showed no significant effects on mean blood pressure (10 microg/kg: 113.8+/-2.0 mmHg vs. 114.4+/-1.6 mmHg; 50 microg/kg: 110+/-2.4 mmHg vs. 109+/-3.2 mmHg; 100 microg/kg: 115.9+/-1.5 mmHg vs. 115.8+/-2.4 mmHg; all P>0.05), heart period (10 microg/kg: 184.7+/-3.9 ms vs. 185.5+/-4.1ms; 50 microg/kg: 185.9+/-4.1 ms vs. 193.4+/-4.5 ms; 100 microg/kg: 137.7+/-4.5 ms vs. 143.9+/-5.6 ms; all P>0.05), or baroreflex sensitivity (10 microg/kg: 0.414+/-0.03 ms/mmHg vs. 0.442+/-0.02 ms/mmHg; 50 microg/kg: 0.453+/-0.04 ms/mmHg vs. 0.439+/-0.01 ms/mmHg; 100 microg/kg: 0.398+/-0.02 ms/mmHg vs. 0.401+/-0.01 ms/mmHg; all P>0.05), however, intravenous injection of ghrelin could decrease mean arterial pressure (115.9+/-1.5 mmHg vs. 108.6+/-3.6 mmHg, P<0.01) and increase heart period (132.4+/-2.8 ms vs. 152.6+/-7.4 ms, P<0.05), but did not change baroreflex sensitivity (0.36+/-0.009 ms/mmHg, P>0.05) in spontaneously hypertensive rats.
Li
Zhao-Feng
ZF
Department of Cardiology, Changhai Hospital, Second Military Medical University, Shanghai 200433, China; Department of Cardiology, No. 88 Hospital of PLA, Tai'an City 271000, China.
Song
Shu-Wei
SW
Qin
Yong-Wen
YW
Zhang
Jian-Liang
JL
Zhao
Xian-Xian
XX
Zhang
Bi-Li
BL
Ren
An-Jing
AJ
Guo
Zhi-Fu
ZF
Zheng
Xing
X
D000818:Animals; D017704:Baroreflex / Q000187:drug effects; D001794:Blood Pressure / Q000187:drug effects*; D054439:Ghrelin / Q000494:pharmacology*; D006339:Heart Rate / Q000187:drug effects; D006801:Humans; D007275:Injections, Intravenous; D008297:Male; D011897:Random Allocation; D051381:Rats; D011918:Rats, Inbred SHR
D054439:Ghrelin