The weeks shown in color represent the start and end points of chemical exposure for each study.

Study Results Study Details References

Results for Chlorpyrifos

Decreased 5HT receptor (type 2) and 5 HTT binding in the whole brain at 1 mg/kg; decreased 5HT receptor (type 2) binding in the whole brain at 2 mg/kg; decreased 5HT receptor (type 1A and type 2) and 5 HTT binding in the whole brain at 5 mg/kg

Subjects: Sprague-Dawley rats

Chemical: Chlorpyrifos

Low doses tested: 1.0 or 5.0 mg/kg bw/d

Route of administration: dissolved in DMSO and injected subcutaneously

Exposure duration: gestational day 9 – gestational day 12 (comparable to human prenatal development from approximately day 1 of week 3 to day 1 of week 5)

Age of measurement: gestational day 17 and 21

Reference [PubMed Link]
Aldridge JE, Seidler FJ, Meyer A, Thillai I, Slotkin TA. 2003. Serotonergic systems targeted by developmental exposure to chlorpyrifos: Effects during different critical periods. Environ Health Perspect 111(14):1736-1743.
Study Results Study Details References

Results for Chlorpyrifos

Increased 5HT receptor (type 1A) binding in the brainstem at 1 and 2 mg/kg; increased 5HTT (serotonin transporter), 5HT (type 1A) and 5HT (type2) binding in the brainstem at 5 mg/kg

Subjects: Sprague-Dawley rats

Chemical: Chlorpyrifos

Low doses tested: 1.0 or 5.0 mg/kg bw/d

Route of administration: dissolved in DMSO and injected subcutaneously

Exposure duration: gestational day 9 – gestational day 12 (comparable to human prenatal development from approximately day 1 of week 3 to day 1 of week 5)

Age of measurement: gestational day 17 and 21

Reference [PubMed Link]
Aldridge JE, Seidler FJ, Meyer A, Thillai I, Slotkin TA. 2003. Serotonergic systems targeted by developmental exposure to chlorpyrifos: Effects during different critical periods. Environ Health Perspect 111(14):1736-1743.
Study Results Study Details References

Results for Chlorpyrifos

Increased 5HTT (serotonin transporter), 5HT (type 1A) and 5HT (type2) binding over all brain regions studied at 1 and 5 mg/kg

Subjects: Sprague-Dawley rats

Chemical: Chlorpyrifos

Low doses tested: 1.0 or 5.0 mg/kg bw/d

Route of administration: dissolved in DMSO and injected subcutaneously

Exposure duration: gestational day 9 – gestational day 12 (comparable to human prenatal development from approximately day 1 of week 3 to day 1 of week 5)

Age of measurement: 60 days of age

Reference [PubMed Link]
Aldridge JE, Seidler FJ, Slotkin TA. 2004. Developmental exposure to chlorpyrifos elicits sex-selective alterations of serotonergic synaptic function in adulthood: Critical periods and regional selectivity for effects on the serotonin transporter, receptor subtypes, and cell signaling. Environ Health Perspect 112(2):148-155.
Study Results Study Details References

Results for Chlorpyrifos

In adolescence: decreased latency during the first trial of a spontaneous alternation test; increased locomotor activity at 1 mg/kg and decreased locomotor activity at 5 mg/kg during late trials of a figure-8 maze test; increased rate of habituation to a figure-8 maze test at 5 mg/kg. In adulthood: increased working and reference memory errors during the early training sessions of a 16-arm radial-maze at 5 mg/kg ; decreased amnesic effects of scopolamine (a cholinergic antagonist) at 5 mg/kg; increased levels of locomotor activity in the elevated plus maze

Subjects: Sprague-Dawley rats

Chemical: Chlorpyrifos

Low doses tested: 1.0 or 5.0 mg/kg bw/d

Route of administration: dissolved in DMSO and injected subcutaneously

Exposure duration: gestational day 9 – gestational day 12 (comparable to human prenatal development from approximately day 1 of week 3 to day 1 of week 5)

Age of measurement: from adolescence through adulthood

Reference [PubMed Link]
Icenogle LM, Christopher NC, Blackwelder WP, Caldwell DP, Qiao D, Seidler FJ, Slotkin TA, Levin ED. 2004. Behavioral alterations in adolescent and adult rats caused by a brief subtoxic exposure to chlorpyrifos during neurulation. Neurotoxicology & Teratology 26(1):95-101.
Study Results Study Details References

Results for Chlorpyrifos

Increased activity of adelylyl cyclase in response to isproterenol, forskolin and Mn2+ in the cortex and striatum at 5 mg/kg

Subjects: Sprague-Dawley rats

Chemical: Chlorpyrifos

Low doses tested: 1.0 or 5.0 mg/kg bw/d

Route of administration: dissolved in DMSO and injected subcutaneously

Exposure duration: gestational day 9 – gestational day 12 (comparable to human prenatal development from approximately day 1 of week 3 to day 1 of week 5)

Age of measurement: 60 days of age

Reference [PubMed Link]
Meyer A, Seidler FJ, Aldridge JE, Tate CA, Cousins MM, Slotkin TA. 2004. Critical periods for chlorpyrifos-induced developmental neurotoxicity: alterations in adenylyl cyclase signaling in adult rat brain regions after gestational or neonatal exposure. Environ Health Perspect 112(3):295-301.
Study Results Study Details References

Results for Chlorpyrifos

Increased activity of adelylyl cyclase in response to isproterenol, forskolin and Mn2+ in the brainstem and cerebellum at 5 mg/kg

Subjects: Sprague-Dawley rats

Chemical: Chlorpyrifos

Low doses tested: 1.0 or 5.0 mg/kg bw/d

Route of administration: dissolved in DMSO and injected subcutaneously

Exposure duration: gestational day 9 – gestational day 12 (comparable to human prenatal development from approximately day 1 of week 3 to day 1 of week 5)

Age of measurement: 60 days of age

Reference [PubMed Link]
Meyer A, Seidler FJ, Aldridge JE, Tate CA, Cousins MM, Slotkin TA. 2004. Critical periods for chlorpyrifos-induced developmental neurotoxicity: alterations in adenylyl cyclase signaling in adult rat brain regions after gestational or neonatal exposure. Environ Health Perspect 112(3):295-301.
Study Results Study Details References

Results for Chlorpyrifos

Increased beta-adrenergic receptor binding in the forebrain at gestational day 21 at 2 and 5 mg/kg

Subjects: Sprague-Dawley rats

Chemical: Chlorpyrifos

Low doses tested: 1.0, 2.0 or 5.0 mg/kg bw/d

Route of administration: dissolved in DMSO and injected subcutaneously

Exposure duration: gestational day 9 – gestational day 11 (comparable to human prenatal development from approximately day 1 of week 3 to day 1 of week 5)

Age of measurement: gestational day 17 and 21

Reference [PubMed Link]
Meyer A, Seidler FJ, Cousins MM, Slotkin TA. 2003. Developmental neurotoxicity elicited by gestational exposure to chlorpyrifos: When is adenylyl cyclase a target? Environ Health Perspect 111(16):1871-1876.
Study Results Study Details References

Results for Chlorpyrifos

Decreased protein/DNA ratio in the brainstem at 2 mg/kg

Subjects: Sprague-Dawley rats

Chemical: Chlorpyrifos

Low doses tested: 1.0, 2.0 or 5.0 mg/kg bw/d

Route of administration: dissolved in DMSO and injected subcutaneously

Exposure duration: gestational day 9 – gestational day 12 (comparable to human prenatal development from approximately day 1 of week 3 to day 1 of week 5)

Age of measurement: gestational days 17 and 21

Reference [PubMed Link]
Qiao D, Seidler FJ, Padilla S, Slotkin TA. 2002. Developmental neurotoxicity of chlorpyrifos: What is the vulnerable period? Environ Health Perspect 110(11):1097-1103.
Study Results Study Details References

Results for Chlorpyrifos

Increased 5HT and DA turn-over in the cerebral cortex

Subjects: Sprague-Dawley rats

Chemical: Chlorpyrifos

Low doses tested: 1.0 or 5.0 mg/kg bw/d

Route of administration: dissolved in DMSO and injected subcutaneously

Exposure duration: gestational day 9 – gestational day 12 (comparable to human prenatal development from approximately day 1 of week 3 to day 1 of week 5)

Age of measurement: post-natal day 30

Reference [PubMed Link]
Slotkin TA, Seidler FJ. 2007. Prenatal chlorpyrifos exposure elicits presynaptic serotonergic and dopaminergic hyperactivity at adolescence: critical periods for regional and sex-selective effects. Reprod Toxicol 23(3):421-427.
Study Results Study Details References

Results for Chlorpyrifos

Decreased m2ACh receptor binding across all regions on post-natal day 60; decreased DNA concentration in the cerebral cortex on post-natal day 30; increased ratio of total protein/DNA and decreased ratio of membrane/total protein in the cerebral cortex; increased ChAT activity in the striatum; decreased HC3 binding in the striatum

Subjects: Sprague-Dawley rats

Chemical: Chlorpyrifos

Low doses tested: 1.0 or 5.0 mg/kg bw/d

Route of administration: dissolved in DMSO and injected subcutaneously

Exposure duration: gestational day 9 – gestational day 12 (comparable to human prenatal development from approximately day 1 of week 3 to day 1 of week 5)

Age of measurement: post-natal day 30 and 60

Reference [PubMed Link]
Qiao D, Seidler FJ, Abreu-Villaca Y, Tate CA, Cousins MM, Slotkin TA. 2004. Chlorpyrifos exposure during neurulation: cholinergic synaptic dysfunction and cellular alterations in brain regions at adolescence and adulthood. Developmental Brain Research 148(1):43-52.
Study Results Study Details References

Results for Chlorpyrifos

Decreased m2ACh receptor binding across all regions on post-natal day 60; increased ChAT activity and decreased HC-3 binding in the hippocampus; decreased DNA concentration on post-natal day 60 and general decreased on DNA content across adolescence and adulthood in the hippocampus

Subjects: Sprague-Dawley rats

Chemical: Chlorpyrifos

Low doses tested: 1.0 or 5.0 mg/kg bw/d

Route of administration: dissolved in DMSO and injected subcutaneously

Exposure duration: gestational day 9 – gestational day 12 (comparable to human prenatal development from approximately day 1 of week 3 to day 1 of week 5)

Age of measurement: post-natal day 30 and 60

Reference [PubMed Link]
Qiao D, Seidler FJ, Abreu-Villaca Y, Tate CA, Cousins MM, Slotkin TA. 2004. Chlorpyrifos exposure during neurulation: cholinergic synaptic dysfunction and cellular alterations in brain regions at adolescence and adulthood. Developmental Brain Research 148(1):43-52.
Study Results Study Details References

Results for Chlorpyrifos

Impaired performance on morris water maze requiring longer to complete the task.

Subjects: HS/Ibg mice

Chemical: Chlorpyrifos

Low doses tested: 3.0 mg/kg bw/d

Route of administration: dissolved in DMSO and injected subcutaneously

Exposure duration: gestational day 9 – gestational day 18 (comparable to human prenatal development from approximately day 1 of week 3 to day 1 of week 11)

Age of measurement: post-natal day 80

Reference [PubMed Link]
Turgeman G, Pinkas A, Slotkin TA, Tfilin M, Langford R, Yanai J. 2011. Reversal of chlorpyrifos neurobehavioral teratogenicity in mice by allographic transplantation of adult subventricular zone-derived neural stem cells. J Neurosci Res 89(8):1185-1193.