Intermittent Exposure to Chlorpyrifos Differentially Impacts Neuroreflex Control of Cardiorespiratory Function in Rats

Thatiany Jardim Batista, Vítor Sampaio Minassa, Andrew Vieira Aitken, Bianca Teixeira Jara, Igor Simões Assunção Felippe, Vanessa Beijamini, Julian Francis Richmond Paton, Leonardo dos Santos, Karla Nívea Sampaio*

*Corresponding author for this work

Research output: Contribution to journalArticle (Academic Journal)peer-review

11 Citations (Scopus)


Previous studies showed that chlorpyrifos (CPF) acute exposure impaired cardiorespiratory reflexes. Evidence also indicates that continuous exposure to organophosphorus compounds impairs cardiovascular function. However, the effect of intermittent exposure to CPF, as may be experienced in the real world, on tonic and reflex cardiorespiratory function remains unexplored. Wistar rats were injected with saline or CPF for 4 weeks (3 times/week) or 12 weeks (once/week) at the doses of 7 mg/kg and 10 mg/kg. After exposure, blood pressure (BP), heart rate (HR), respiratory rate (fR), tidal volume (VT), and minute volume (VE) were recorded. Systolic BP and pulse interval (PI) variability, HR spectrum, spontaneous baroreflex and chemoreflex function were also evaluated. Plasma butyrylcholinesterase and brainstem acetylcholinesterase activities were quantified. Enzymatic activity of the CPF animals was reduced after both treatment periods. Baseline BP, HR, and fR, as well as systolic BP and PI variability indices, did not change, after CPF treatment. VT and VE were elevated in CPF animals. CPF exposure increased the very low-frequency component of the HR spectrum. Baroreflex gain was reduced after CPF 4-week exposure. Chemoreflex bradycardia was reduced in the CPF-treated rats. These data show that intermittent exposure to CPF impairs cardiorespiratory function in rats. These results may have important clinical implications for workers seasonally exposed to these compounds.

Original languageEnglish
Pages (from-to)548-564
Number of pages17
JournalCardiovascular Toxicology
Issue number6
Early online date16 May 2019
Publication statusPublished - 1 Dec 2019

Bibliographical note

The acceptance date for this record is provisional and based upon the month of publication for the article.


  • Acetylcholinesterase
  • Baroreflex
  • Butyrylcholinesterase
  • Cardiovascular variability
  • Chemoreflex
  • Chlorpyrifos


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