Chronic fluoxetine treatment enhances sympathetic activities associated with abnormality of baroreflex function in conscious normal rats.

Data regarding the effects of selective serotonin reuptake inhibitors (SSRIs), which are a common type of antidepressants, on cardiovascular autonomic function are inconsistent. The present study was conducted to determine the effects of chronic fluoxetine, an SSRI, on blood pressure, cardiac autonomic nervous activities and baroreflex control of heart rate. Male Sprague-Dawley rats were treated with fluoxetine (10mg/kg day, p.o.) or saline for 14 weeks. Baroreflex function was determined by the sigmoid logistic method based on the heart rate responses to changes in blood pressure elicited by phenylephrine or sodium nitroprusside infusions. Cardiac sympathetic and parasympathetic tones were determined after methylatropine and propranolol treatments. Vascular responsiveness to acetylcholine, phenylephrine and sodium nitroprusside, and cardiac responsiveness to isoproterenol were determined after ganglionic blockade. Chronic fluoxetine treatment increased plasma levels of adrenaline and noradrenaline, but not nitric oxide. Elevation of blood pressure and heart rate by chronic fluoxetine was accompanied by baroreflex resetting and depressed baroreflex sensitivity. Elevated heart rate was mediated by enhanced sympathetic and depressed parasympathetic tones. The lowered baroreflex sensitivity might be attributed to attenuation of the parasympathetic component of baroreflex function. Chronic fluoxetine also diminished cardiac and vascular responsiveness to isoproterenol and acetylcholine, respectively. The plasma levels of adrenaline and noradrenaline were highly correlated with blood pressure, heart rate and baroreflex sensitivity. In conclusion, our results demonstrate that chronic fluoxetine treatment in normal rats induced predominant sympathoexcitation and depressed parasympathetic activity leading to mild hypertension, tachycardia, and impairment of baroreflex function.

Validation of the applicability of the traditional Chinese version of the University of Pennsylvania Smell Identification Test in patients with chronic rhinosinusitis.

The 40-item University of Pennsylvania Smell Identification Test (UPSIT) is the most widely used smell test in the world. Presently, culturally modified versions of this test are available in multiple languages. A traditional Chinese version of the UPSIT (UPSIT-TC) has been developed for administration in Taiwan. The purpose of this study was to investigate the validity and reliability of the UPSIT-TC in Taiwanese patients with chronic rhinosinusitis (CRS). The phenylethyl alcohol (PEA) odor detection threshold test, the North American version of UPSIT (UPSIT-NA), and the UPSIT-TC were administered to 40 healthy subjects and to 100 CRS patients before and after functional endoscopic sinus surgery (FESS). The UPSIT-TC showed good internal consistency (Cronbach's alpha = 0.887, 0.886, and 0.870 at three test occasions) and test-retest reliability (p < 0.001). The scores of UPSIT-TC were significantly correlated to the PEA thresholds (p < 0.001). The UPSIT-TC scores were significantly higher than those of the UPSIT-NA (p = 0.028) when analysis was performed with logistic regression with independent variables including test occasions (before or after FESS), test methods (UPSIT-NA or UPSIT-TC), status of polyp (with or without), and PEA thresholds (improved or did not improve). In addition, there were significant between-group differences in UPSIT-TC scores including healthy versus CRS, CRS with polyps versus CRS without polyps, and PEA thresholds improved versus PEA thresholds which did not improve. The UPSIT-TC is reliable and valid for measuring olfactory function in Taiwanese patients with rhinosinusitis. In addition, the UPSIT-TC clearly resulted in better performance than that of UPSIT-NA.