Central cardiovascular action of urotensin II in conscious rats.

Abstract

OBJECTIVE:

To examine the central cardiovascular action of urotensin II in conscious rats.

METHODS:

Intracerebroventricular (ICV) injections of urotensin II (1 and 10 nmol) were carried out in conscious Wistar rats. The effects of intravenous (i.v.) urotensin II (10 nmol) were also determined.

RESULTS:

The ICV injection of urotensin II at a dose of 1 nmol did not alter the arterial pressure or heart rate significantly, while 10 nmol urotensin II increased the arterial pressure and heart rate. The mean arterial pressure at 5 min of ICV urotensin II was 121 +/- 4 mmHg, which was significantly higher than that obtained by ICV injection of artificial cerebrospinal fluid (107 +/- 3 mmHg, P <0.05). In addition, significant increases in heart rate were observed 5-15 min after ICV urotensin II. Pre-treatment with pentolinium (5 mg/kg, i.v.) significantly attenuated the increases in mean arterial pressure (20 +/- 3 versus 8 +/- 2 mmHg, P <0.01) and heart rate (78 +/- 18 versus 7 +/- 5 beats/min, P <0.05) induced by ICV urotensin II. On the other hand, i.v. injection of urotensin II (10 nmol) elicited a depressor response associated with tachycardia; mean arterial pressure 5 min after injection was significantly lower in the urotensin II-injected rats (89 +/- 5 mmHg) than in the control rats (102 +/- 2 mmHg, P <0.05), and the heart rate was significantly higher in the former (402 +/- 11 versus 360 +/- 9 beats/min, respectively, P <0.05).

CONCLUSIONS:

Central urotensin II produces pressor and tachycardic responses through sympathetic activation, while peripheral urotensin II exerts a vasodilation-mediated depressor response in conscious rats.

• Authors: Yingzi Lin, Takuya Tsuchihashi, Kiyoshi Matsumura, Isao Abe, Mitsuo Iida
• Journal: Journal of hypertension (J Hypertens) Vol. 21 Issue 1 Pg. 159-65 (Jan 2003) ISSN: 0263-6352 [Print] England
• PMID: 12544448 (Publication Type: Journal Article)

Chemical References

• Antihypertensive Agents
• Urotensins
• urotensin II
• Pentolinium Tartrate

Topics

• Animals
• Antihypertensive Agents (pharmacology)
• Blood Pressure (drug effects)
• Brain (physiology)
• Cardiovascular System (drug effects)
• Heart Rate (drug effects)
• Injections, Intravenous
• Injections, Intraventricular
• Male
• Pentolinium Tartrate (pharmacology)
• Rats
• Rats, Wistar
• Urotensins (administration & dosage)