Effects of AF-DX116 and Other Muscarinic Receptor Antagonists on Orthostatic Hypotension in Autonomic Imbalanced (SART-Stressed) Rats

Hata, Taeko; Funakami, Yoshinori; Itoh, Eiji

doi:10.1254/jphs.fp0040774

Cited by 5 publications

(11 citation statements)

References 23 publications

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“…)-anesthetized rats were restrained on a board in a supine position according to our previous report. 2) In the paper, blood pressure, heart rate and tilting parameters obtained from carotid arteries were reported to be similar to those obtained from the femoral arteries, and difference of parameters between unstressed and SART-stressed rats was large and clear in the data from carotid arteries compared to those from femoral arteries. Then the carotid artery was used in this paper.…”

Section: Experimental Animalsmentioning

confidence: 73%

“…It has been reported that SART-stressed rats are in the state of continuous hypotension 1) and tachycardia, 15) and have greater drop in blood pressure at standing (MD), lower %re-flex and tend to have OH more easily. 2,19) The compensatory reflex mechanism, which should work against hypotension caused by tilting, is thought to be abnormal in the stressed rats. In the present study, the role played by the autonomic nervous system, particularly b-adrenoceptors, was investigated.…”

Section: Discussionmentioning

confidence: 99%

“…18,19) Effects of hexamethonium, an autonomic ganglion blocker, isoproterenol, a b-adrenoceptor stimulant and badrenoceptor antagonists on OH induced by HUT were studied using the above-described SART-stressed rats. Results of the study were obtained in mean blood pressure measured automatically using an electrocardiogram and blood pressure-waveform recognition frequency change analysis software (Fluclet ® ).…”

Section: )mentioning

confidence: 99%

“…1 and Table 1 based on mean blood pressure and heart rate that were mea-sured automatically by Fluclet, were similar to data based on systolic blood pressure obtained in analog processing reported in previous studies. 1,2,18,19) Roles Played by the Autonomic Nervous System on OH Figure 2 shows changes in blood pressure and heart rate in HUT following administration of hexamethonium. In unstressed rats, decreases in blood pressure after standing were greater than those without hexamethonium, the time-related curve moved downward, and the recovery of blood pressure was poor.…”

Section: Effects Of Sart Stress On Blood Pressure and Heartmentioning

confidence: 99%

“…We have been studying the relationship. 1,2) We receive various kinds of stress in our everyday life. Among many stressors, those we talk about daily seem to be psychological stresses arising from jobs or personal relationships.…”

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confidence: 99%

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Effects of Some .BETA.-Adrenoceptor Antagonists on Orthostatic Hypotension in Repeatedly Cold- (SART-) Stressed Rats

Funakami

Hata

Itoh

et al. 2007

Biological & Pharmaceutical Bulletin

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Hypotension has not been recognized as a disease and has been neglected till now, because the symptoms are quiet and rarely life-threatening unlike those of hypertension. However, many people suffer from hypotension, and these people also suffer from orthostatic hypotension (OH). While the role played by stress in hypertension is often talked about, there are nearly no reports on the relationship between hypotension and stress and that between OH and stress just like there are nearly no reports on hypotension itself. We have been studying the relationship.1,2) We receive various kinds of stress in our everyday life. Among many stressors, those we talk about daily seem to be psychological stresses arising from jobs or personal relationships. The majority of these stressors are anger and hostility, as well as suppression and anxiety. Hypotensive patients often manifest symptoms when they have these psychological factors.3) Hypotension also occurs when patients are under excessive environmental stress, such as cold and heat. Many cases are thought to be induced not by organic injury but by the breakdown of circulatory regulation due to the dysfunction of the hypothalamo-autonomic nervous system. 4)Various tests often find no abnormalities, when the breakdown of circulatory regulation due to autonomic dysfunction occurs in patients with normal circulatory functions. Headup tilt test (HUT) 5) is one method often used to induce OH in humans for the purpose of testing OH of undetermined origin and neurally mediated syncope (NMS). However, details of HUT vary by researchers, such as degree of HUT or the positive criteria of OH and NMS. The dose of isoproterenol, which is often used in HUT in order to increase the induction rate of NMS, also varies by researchers. [6][7][8][9][10][11] In the present study, the role played by the autonomic nervous system, especially b-adrenoceptors in OH was investigated by performing HUT to SART (specific alternation of rhythm in temperature) 12) -stressed rats with various symptoms of autonomic imbalance 13) and hypotension. 1) There are many people who complain of poor physical condition at a season with severe temperature changes or at a change of seasons, such as early spring or the beginning of autumn. SART-stressed animals are created in simulation of such a state by rearing in an environment where temperature changes rapidly, intermittently and repeatedly between room temperature and low temperature. 12,14) The animals are used widely in research as an autonomic imbalance model animal of systemic parasympathetic hypertonia and sympathetic hypotonia 13) based on results of, the Aschner's test, Mecholyl test and GSR (galvanic skin response) test.SART-stressed rats have been reported to have increased heart rate, 12) abnormal electrocardiogram (ECG), 15) continuous hypotension 1) and other circulatory changes. 16,17) SARTstressed rats develop OH easily when subjected to HUT.2) It has also been reported that these symptoms are improved by muscarinic M 2 -receptor antagonists. 18,19) E...

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Section: Experimental Animalsmentioning

confidence: 73%