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 frequency of head dipping in plus-maze at 3 mg/kg for males

Subjects: CD-1 mice

Chemical: Chlorpyrifos

Low doses tested: 3.0 mg/kg bw/d

Other doses tested: 6.0 mg/kg bw/d

Route of administration: dissolved in peanut oil and delivered by oral gavage

Exposure duration: gestational day 15 – gestational day 18 (comparable to human prenatal development from approximately day 1 of week 7 to day 1 of week 11)

Age of measurement: 60 through 120 days of age

Reference [PubMed Link]
Ricceri L, Venerosi A, Capone F, Cometa MF, Lorenzini P, Fortuna S, Calamandrei G. 2006. Developmental neurotoxicity of organophosphorous pesticides: fetal and neonatal exposure to chlorpyrifos alters sex-specific behaviors at adulthood in mice. Toxicol Sci 93(1):105-113.
Study Results Study Details References

Results for Chlorpyrifos

Females only. Decreased time spent in the center of the light compartment of a light/dark box and decreased number of box switches at 1 mg/kg; decreased percent time in open arms and decreased number of open arm entries at 1.0 mg/kg. All findings indicate increased anxiety.

Subjects: CD-1 mice

Chemical: Chlorpyrifos

Low doses tested: 0.2, 1.0 or 5.0 mg/kg bw/d

Route of administration: dissolved in corn oil and delivered via oral gavage

Exposure duration: gestational day 15 – post-natal day 14 (comparable to human prenatal development from approximately day 1 of week 7 to day 1 of week 32)

Age of measurement: in adulthood

Reference [PubMed Link]
Braquenier JB, Quertemont E, Tirelli E, Plumier JC. 2010 Mar-2010 Apr 30. Anxiety in adult female mice following perinatal exposure to chlorpyrifos. Neurotoxicol Teratol 32(2):234-239.
Study Results Study Details References

Results for Chlorpyrifos

Increased 5HT receptor (type 1A and type 2) binding in the forebrain at 1 and 5 mg/kg; increased 5HT receptor (type 1A and type 2) and 5HTT binding at 2 mg/kg; decreased basal activity of adenylyl cyclase in response to forskolin in the forebrain

Subjects: Sprague-Dawley rats

Chemical: Chlorpyrifos

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

Other doses tested: 10, 20 or 40 mg/kg bw/d

Route of administration: dissolved in DMSO and injected subcutaneously

Exposure duration: gestational day 17 – gestational day 20 (comparable to human prenatal development from approximately day 1 of week 7 to day 1 of week 14)

Age of measurement: gestational day 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 activity of adenylyl cyclase in response to forskolin in the brainstem at 2 mg/kg; increased basal activity of adenylyl cyclase in the brainstem

Subjects: Sprague-Dawley rats

Chemical: Chlorpyrifos

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

Other doses tested: 10, 20 or 40 mg/kg bw/d

Route of administration: dissolved in DMSO and injected subcutaneously

Exposure duration: gestational day 17 – gestational day 20 (comparable to human prenatal development from approximately day 1 of week 7 to day 1 of week 14)

Age of measurement: gestational day 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; increased 5HT binding markers in the midbrain at 1 mg/kg in both sexes; increased 5HT binding markers in the striatum of males at 1 and 5 mg/kg; increased 5HT1A binding in the striatum of females at 1 mg/kg; increased overall 5HT binding markers in the midbrain at 5 mg/kg in males; decreased activity of adenylyl cyclase in response to 5HT (serotonin) relative to absence of 5HT in the cerebral cortex (both sexes) and in the midbrain (only females) at 1 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 17 – gestational day 20 (comparable to human prenatal development from approximately day 1 of week 7 to day 1 of week 14)

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

Increased 5HTT binding (serotonin transporter) in the hippocampus at 1 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 17 – gestational day 20 (comparable to human prenatal development from approximately day 1 of week 7 to day 1 of week 14)

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

Increased overall 5HT binding markers 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 17 – gestational day 20 (comparable to human prenatal development from approximately day 1 of week 7 to day 1 of week 14)

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

Decreased 5-hydroxytryptamine serotonin (5HT) content in cerebral cortex and midbrain at 5 mg/kg; increased 5HT content in striatum at 5 mg/kg; increased 5HT turnover in cerebral cortex, midbrain, and striatum at 1 and 5 mg/kg; increased dopamine turnover in cerebral cortex, midbrain, 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 sub-cutaneously

Exposure duration: gestational day 17 – gestational day 20 (comparable to human prenatal development from approximately day 1 of week 7 to day 1 of week 14)

Age of measurement: 60 days of age

Reference [PubMed Link]
Aldridge JE, Meyer A, Seidler FJ, Slotkin TA. 2005. Alterations in central nervous system serotonergic and dopaminergic synaptic activity in adulthood after prenatal or neonatal chlorpyrifos exposure. Environ Health Perspect 113(8):1027-1031.
Study Results Study Details References

Results for Chlorpyrifos

Decreased 5-hydroxytryptamine serotonin (5HT) content in hippocampus at 5 mg/kg; increased 5HT turnover in hippocampus at 1 and 5 mg/kg; decreased dopamine content in hippocampus 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 sub-cutaneously

Exposure duration: gestational day 17 – gestational day 20 (comparable to human prenatal development from approximately day 1 of week 7 to day 1 of week 14)

Age of measurement: 60 days of age

Reference [PubMed Link]
Aldridge JE, Meyer A, Seidler FJ, Slotkin TA. 2005. Alterations in central nervous system serotonergic and dopaminergic synaptic activity in adulthood after prenatal or neonatal chlorpyrifos exposure. Environ Health Perspect 113(8):1027-1031.
Study Results Study Details References

Results for Chlorpyrifos

Decreased 5-hydroxytryptamine serotonin (5HT) content in the brainstem at 5 mg/kg; increased 5HT turnover in the brainstem 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 sub-cutaneously

Exposure duration: gestational day 17 – gestational day 20 (comparable to human prenatal development from approximately day 1 of week 7 to day 1 of week 14)

Age of measurement: 60 days of age

Reference [PubMed Link]
Aldridge JE, Meyer A, Seidler FJ, Slotkin TA. 2005. Alterations in central nervous system serotonergic and dopaminergic synaptic activity in adulthood after prenatal or neonatal chlorpyrifos exposure. Environ Health Perspect 113(8):1027-1031.
Study Results Study Details References

Results for Chlorpyrifos

Increased levels of neuronal and myelin markers over all brain regions studied at 5 mg/kg at gestational day 21

Subjects: Sprague-Dawley rats

Chemical: Chlorpyrifos

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

Other doses tested: 10, 20 or 40 mg/kg bw/d

Route of administration: dissolved in DMSO and injected subcutaneously

Exposure duration: gestational day 17 – gestational day 20 (comparable to human prenatal development from approximately day 1 of week 7 to day 1 of week 14)

Age of measurement: gestational day 21 and post-natal 5, 10, 15, 21 and 30

Reference [PubMed Link]
Garcia SJ, Seidler FJ, Slotkin TA. 2003. Developmental neurotoxicity elicited by prenatal or postnatal chlorpyrifos exposure: Effects on neurospecific proteins indicate changing vulnerabilities. Environ Health Perspect 111(3):297-304.
Study Results Study Details References

Results for Chlorpyrifos

Increased levels of neuronal and myelin markers over all brain regions studied at 5 mg/kg at gestational day 21

Subjects: Sprague-Dawley rats

Chemical: Chlorpyrifos

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

Other doses tested: 10, 20 or 40 mg/kg bw/d

Route of administration: dissolved in DMSO and injected subcutaneously

Exposure duration: gestational day 17 – gestational day 20 (comparable to human prenatal development from approximately day 1 of week 7 to day 1 of week 14)

Age of measurement: gestational day 21 and post-natal 5, 10, 15, 21 and 30

Reference [PubMed Link]
Garcia SJ, Seidler FJ, Slotkin TA. 2003. Developmental neurotoxicity elicited by prenatal or postnatal chlorpyrifos exposure: Effects on neurospecific proteins indicate changing vulnerabilities. Environ Health Perspect 111(3):297-304.
Study Results Study Details References

Results for Chlorpyrifos

Decreased latency to perform spontaneous alternation test; slower habituation on Figure-8 Maze Locomotor activity among females; increased working and reference memory errors on 16-Arm Radial Maze Acquisition at 1 mg/kg among females; responses to scopolamine and mecamylamine are also reported.

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 sub-cutaneously

Exposure duration: gestational day 17 – gestational day 20 (comparable to human prenatal development from approximately day 1 of week 7 to day 1 of week 14)

Age of measurement: 4 through 17 weeks of age

Reference [PubMed Link]
Levin ED, Addy N, Baruah A, Elias A, Christopher NC, Seidler FJ, Slotkin TA. 2002. Prenatal chlorpyrifos exposure in rats causes persistent behavioral alterations. Neurotoxicology & Teratology 24(6):733-741.
Study Results Study Details References

Results for Chlorpyrifos

Decreased Beta-adrenergic receptor binding in the striatum of females at 5 mg/kg; increased Adenylyl Cyclase activity in response to forskolin and Mn2+ in the striatum of males 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 17 – gestational day 20 (comparable to human prenatal development from approximately day 1 of week 7 to day 1 of week 14)

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 basal adenylyl cyclase activity and adenylyl cyclase activity in response to forskolin, isoproterenol, and Mn2+ in the hippocampus 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 17 – gestational day 20 (comparable to human prenatal development from approximately day 1 of week 7 to day 1 of week 14)

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

Decreased beta-adrenergic receptor binding in the brainstem of females; increased basal and stimulated activity of adelylyl cyclase in the cerebellum of females

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 17 – gestational day 20 (comparable to human prenatal development from approximately day 1 of week 7 to day 1 of week 14)

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

Decreased beta-adrenergic receptor binding in the forebrain at 2 mg/kg

Subjects: Sprague-Dawley rats

Chemical: Chlorpyrifos

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

Other doses tested: 10, 20 or 40 mg/kg bw/d

Route of administration: dissolved in DMSO and injected subcutaneously

Exposure duration: gestational day 17 – gestational day 20 (comparable to human prenatal development from approximately day 1 of week 7 to day 1 of week 14)

Age of measurement: gestational day 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 Beta-adrenergic receptor binding at 1 and 2 mg/kg in the brainstem; increased basal and isoproterenol-stimulated activity of adenylyl cyclase at 5 mg/kg; increased adenylyl cyclase activity in response to forskolin and Mn2+ at 2 mg/kg

Subjects: Sprague-Dawley rats

Chemical: Chlorpyrifos

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

Other doses tested: 10, 20 or 40 mg/kg bw/d

Route of administration: dissolved in DMSO and injected subcutaneously

Exposure duration: gestational day 17 – gestational day 20 (comparable to human prenatal development from approximately day 1 of week 7 to day 1 of week 14)

Age of measurement: gestational day 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

Increased protein/DNA ratio in the brainstem at 1 and 2 mg/kg; decreased cholinesterase in the brainstem at 2 and 5 mg/kg; decreased m2-AChRs in the brainstem at 5 mg/kg

Subjects: Sprague-Dawley rats

Chemical: Chlorpyrifos

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

Other doses tested: 10, 20 or 40 mg/kg bw/d

Route of administration: dissolved in DMSO and injected subcutaneously

Exposure duration: gestational day 17 – gestational day 20 (comparable to human prenatal development from approximately day 1 of week 7 to day 1 of week 14)

Age of measurement: gestational day 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 ratio of cell protein to DNA and decreased ratio of membrane to total protein 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 17 – gestational day 20 (comparable to human prenatal development from approximately day 1 of week 7 to day 1 of week 14)

Age of measurement: birth through 60 days of age

Reference [PubMed Link]
Qiao D, Seidler FJ, Tate CA, Cousins MM, Slotkin TA. 2003. Fetal chlorpyrifos exposure: Adverse effects on brain cell development and cholinergic biomarkers emerge postnatally and continue into adolescence and adulthood. Environ Health Perspect 111(4):536-544.
Study Results Study Details References

Results for Chlorpyrifos

Increased 5HT content in the striatum; increased DA turn-over in the cerebral cortex; increased 5HT turn-over in males at both doses across all the regions while for females only 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 17 – gestational day 20 (comparable to human prenatal development from approximately day 1 of week 7 to day 1 of week 14)

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

Increased 5HT turn-over in males at both doses across all the regions while for females only 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 17 – gestational day 20 (comparable to human prenatal development from approximately day 1 of week 7 to day 1 of week 14)

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

Increased ChAT activity in the forebrain through post-natal day 15 at 1 mg/kg, and decreased ChAT activity at 21 days of age at 1 mg/kg; decreased HC-3 binding; decreased DNA concentration (cell packing density); decreased ratio of total cell protein to DNA at early ages, changing to increases at later ages; decreased membrane protein concentration; decreased ratio of membrane to total protein at later ages

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 17 – gestational day 20 (comparable to human prenatal development from approximately day 1 of week 7 to day 1 of week 14)

Age of measurement: birth through 60 days of age

Reference [PubMed Link]
Qiao D, Seidler FJ, Tate CA, Cousins MM, Slotkin TA. 2003. Fetal chlorpyrifos exposure: Adverse effects on brain cell development and cholinergic biomarkers emerge postnatally and continue into adolescence and adulthood. Environ Health Perspect 111(4):536-544.
Study Results Study Details References

Results for Chlorpyrifos

Increased 5HT turn-over in males at both doses across all the regions while for females only 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 17 – gestational day 20 (comparable to human prenatal development from approximately day 1 of week 7 to day 1 of week 14)

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.