Background: Specific alternation of rhythm in temperature (SART)-stressed rats, an animal model of autonomic imbalance, exhibit low blood pressure and tachycardia during consciousness and under anesthesia. In addition, these rats easily develop orthostatic hypotension (OH) as a response to postural manipulation. Hence, we studied the influence of the adrenalin α1-receptor agonist phenylephrine on stress-induced OH in SART-stressed rats and unstressed rats.
Methods: Male Wistar rats weighing 250-300 g were used. Rats were fixed in the supine position under urethane anesthesia. Blood pressure was directly measured from the left common carotid artery and ECG was recorded simultaneously.
Results: The maximum decrease in blood pressure and the area under the blood pressure-time curve were both large, while the %reflex was small in the SART-stressed rats compared with unstressed rats. In the SART-stressed rats, prolonged intravenous administration of phenylephrine reduced OH at a dose that barely affected unstressed rats.
Conclusion: The results suggested that sympathetic dysfunction is a factor underlying SART stress-induced OH.
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http://dx.doi.org/10.1186/1751-0759-4-13 | DOI Listing |
Life Sci
February 2017
Department of Pharmacological Research, Institute of Bio-Active Science, Nippon Zoki Pharmaceutical Co., Ltd, 442-1, Kato-shi, Hyogo, Japan. Electronic address:
Aims: Neurotropin® (NTP), an analgesic for chronic pain, has antihyperalgesic effects in specific alternation of rhythm in temperature (SART)-stressed rats. Previous studies have shown that SART stress induces hyperalgesia, as well as post-translational modification of proteins (including substrates for calpain, a calcium-dependent cysteine protease) in the mesencephalon of rats. To better understand the mechanism of action of NTP, we investigated whether SART stress activates calpain in the mesencephalon of rats and whether NTP inhibits this activation.
View Article and Find Full Text PDFEur J Pharmacol
August 2016
Inflammation Drug Discovery Unit, Pharmaceutical Research Division, Takeda Pharmaceutical Company Limited, 26-1 Muraoka Higashi 2-chome Fujisawa, Kanagawa 251-8555, Japan. Electronic address:
Fibromyalgia is characterized by chronic widespread musculoskeletal pain. A hypofunction in descending pain inhibitory systems is considered to be involved in the chronic pain of fibromyalgia. We examined functional changes in descending pain inhibitory systems in rats with specific alternation of rhythm in temperature (SART) stress, by measuring the strength of diffuse noxious inhibitory controls (DNIC).
View Article and Find Full Text PDFBiopsychosoc Med
October 2010
Kinki University School of Pharmacy, Kowakae 3-4-1, Higashi-Osaka, 577-8502, Japan.
Background: Specific alternation of rhythm in temperature (SART)-stressed rats, an animal model of autonomic imbalance, exhibit low blood pressure and tachycardia during consciousness and under anesthesia. In addition, these rats easily develop orthostatic hypotension (OH) as a response to postural manipulation. Hence, we studied the influence of the adrenalin α1-receptor agonist phenylephrine on stress-induced OH in SART-stressed rats and unstressed rats.
View Article and Find Full Text PDFBiol Pharm Bull
February 2007
Department of Pharmacology, Faculty of Pharmacy, Kinki University, Higashi-Osaka, Japan.
Rats stressed by specific alternation of rhythm in temperature (SART) show various symptoms of disautonomia, increased pulse rates, continuous hypotension, and severe orthostatic hypotension (OH) when they are subjected to postural change. The OH symptoms are improved by muscarinic M2-receptor blockers. In the present study, effects of beta-adrenoceptor blocking agents on OH in SART-stressed rats were investigated.
View Article and Find Full Text PDFJ Pharmacol Sci
March 2005
Department of Pharmacology, Faculty of Pharmaceutical Sciences, Kinki University, Higashi-Osaka.
SART (specific alternation of rhythm in temperature)-stressed rats are an animal model of autonomic imbalance created by exposing animals to repeated cold stress. The SART-stressed rats have been shown to easily develop orthostatic hypotension (OH). In this study, effects of AF-DX116, a selective M(2) antagonist, and other muscarinic receptor antagonists on OH were investigated in SART-stressed and unstressed rats.
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