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Miguel JP, Dias ADC, Bettini NR, Sousa SABAD, Durão MPL, Oliveira LVDC, Monedeiro F, Ramalho LNZ, Branco LGS, Sabino JPJ, Durand MDT. Cigarette smoke exposure causes systemic and autonomic cardiocirculatory changes in rats depending on the daily exposure dose. Life Sci 2021; 277:119498. [PMID: 33864817 DOI: 10.1016/j.lfs.2021.119498] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2020] [Revised: 03/29/2021] [Accepted: 03/31/2021] [Indexed: 11/15/2022]
Abstract
AIMS To evaluate the systemic changes and autonomic cardiocirculatory control of awaken rats chronically exposed to the cigarette smoke (CS) of 1 or 2 cigarettes/day. MAIN METHODS Rats were exposed to clean air (control) or cigarette smoke of 1 (CS1) or 2 (CS2) cigarettes/animal/day for 30 days. Then, arterial pressure (AP) and heart rate (HR) were recorded in conscious rats to assess spontaneous baroreflex sensitivity and HR and AP variabilities. Evoked baroreflex and cardiac autonomic tone were evaluated by vasoactive drugs and autonomic blockers, respectively. In another group, ventilatory and cardiovascular parameters were recorded under hypoxia and hypercapnia stimulus. At the end of protocols, heart, lung, kidneys and liver were collected for histological analysis. KEY FINDINGS Rats exposed to CS showed morphological changes, being more evident in the CS2 group. Also, less weight gain and cardiac hypertrophy were prominent in CS2 rats. Basal AP and HR, spontaneous baroreflex sensitivity and cardiovascular variabilities were similar among groups. CS exposure progressively blunted the bradycardia response to phenylephrine (-2.2 ± 0.1 vs. -1.7 ± 0.2 vs. -1.5 ± 0.2) while the tachycardia response to sodium nitroprusside was slightly increased compared to control. Vagal tone was not affected by CS, but CS2 rats exhibited higher sympathetic tone (-25 ± 4 vs. -28 ± 4 vs. -56 ± 9) and lower intrinsic HR (411 ± 4 vs. 420 ± 8 vs. 390 ± 6). Exposure to CS of 2 cigarettes also exacerbated the reflex cardiovascular and ventilatory responses to hypoxia and hypercapnia. SIGNIFICANCE CS exposure for 30 days promoted systemic changes and autonomic cardiocirculatory dysfunction in rats depending on the daily exposure dose.
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Affiliation(s)
- João Paulo Miguel
- Medical School, University of Ribeirão Preto, Ribeirão Preto, SP, Brazil
| | | | | | | | | | - Lucas Vaz de Castro Oliveira
- Department of Biophysics and Physiology, Postgraduate Program in Pharmaceutical Sciences, Federal University of Piaui, Teresina, PI, Brazil
| | - Fernanda Monedeiro
- Department of Chemistry, Physiology and Basic Pathology, University of São Paulo, Ribeirão Preto, SP, Brazil
| | | | - Luiz Guilherme S Branco
- Department of Morphology, Physiology and Basic Pathology, University of São Paulo, Ribeirão Preto, SP, Brazil
| | - João Paulo Jacob Sabino
- Department of Biophysics and Physiology, Postgraduate Program in Pharmaceutical Sciences, Federal University of Piaui, Teresina, PI, Brazil
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