Skip to main content
Environmental Health Perspectives logoLink to Environmental Health Perspectives
. 2002 Jun;110(Suppl 3):369–376. doi: 10.1289/ehp.02110s3369

Evidence that GABAergic neurons in the preoptic area of the rat brain are targets of 2,3,7,8-tetrachlorodibenzo-p-dioxin during development.

Linda E Hays 1, Clifford D Carpenter 1, Sandra L Petersen 1
PMCID: PMC1241185  PMID: 12060831

Abstract

Developmental exposure to 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) interferes with masculinization and defeminization of male sexual behaviors and gonadotropin release patterns. We previously demonstrated that the mRNA encoding the arylhydrocarbon receptor (AhR), a protein that mediates TCDD effects, is found in brain regions that control reproductive functions, most notably in the preoptic area (POA). The pattern of distribution of the AhR gene closely overlaps that of an enzyme necessary for Gamma-aminobutyric acid (GABA) synthesis, glutamic acid decarboxylase (GAD) 67. To test the hypothesis that GABAergic neurons in the POA are targets of TCDD during development, we used dual-label in situ hybridization histochemistry (ISHH) to co-localize GAD and AhR mRNAs in the region. In addition, we used ISHH to determine the effects of TCDD (1 microg/kg body weight, gestational day 15) on GAD 67 gene expression in POA regions in pups examined on postnatal day 3. We found that virtually all GABAergic neurons in the POA expressed the AhR gene. Furthermore, GAD 67 mRNA levels were higher in females than in males in the rostral POA/anteroventral periventricular nucleus (rPOA/AVPV) and in the rostral portion of the medial preoptic nucleus (MPN). TCDD abolished sex differences in the rPOA/AVPV but had no effect in the rostral MPN. In the caudal MPN, there were no sex differences in GAD 67 gene expression, but TCDD depressed expression specifically in males. Our findings demonstrate that GABAergic neurons in the brain are targets of TCDD and may mediate developmental effects of this contaminant on reproductive function.

Full Text

The Full Text of this article is available as a PDF (592.8 KB).

Selected References

These references are in PubMed. This may not be the complete list of references from this article.

  1. Barraclough C. A. Modifications in the CNS regulation of reproduction after exposure of prepubertal rats to steroid hormones. Recent Prog Horm Res. 1966;22:503–539. doi: 10.1016/b978-1-4831-9825-5.50016-6. [DOI] [PubMed] [Google Scholar]
  2. Barraclough C. A., Turgeon J. L. Ontogeny of development of the hypothalamic regualtion of gonadotropin secretion: effects of perinatal sex steroid exposure. Symp Soc Dev Biol. 1975;(33):255–273. doi: 10.1016/b978-0-12-612979-3.50018-2. [DOI] [PubMed] [Google Scholar]
  3. Bertazzi P. A., Bernucci I., Brambilla G., Consonni D., Pesatori A. C. The Seveso studies on early and long-term effects of dioxin exposure: a review. Environ Health Perspect. 1998 Apr;106 (Suppl 2):625–633. doi: 10.1289/ehp.98106625. [DOI] [PMC free article] [PubMed] [Google Scholar]
  4. Birnbaum L. S. The mechanism of dioxin toxicity: relationship to risk assessment. Environ Health Perspect. 1994 Nov;102 (Suppl 9):157–167. doi: 10.1289/ehp.94102s9157. [DOI] [PMC free article] [PubMed] [Google Scholar]
  5. Bjerke D. L., Brown T. J., MacLusky N. J., Hochberg R. B., Peterson R. E. Partial demasculinization and feminization of sex behavior in male rats by in utero and lactational exposure to 2,3,7,8-tetrachlorodibenzo-p-dioxin is not associated with alterations in estrogen receptor binding or volumes of sexually differentiated brain nuclei. Toxicol Appl Pharmacol. 1994 Aug;127(2):258–267. doi: 10.1006/taap.1994.1160. [DOI] [PubMed] [Google Scholar]
  6. Bjerke D. L., Peterson R. E. Reproductive toxicity of 2,3,7,8-tetrachlorodibenzo-p-dioxin in male rats: different effects of in utero versus lactational exposure. Toxicol Appl Pharmacol. 1994 Aug;127(2):241–249. doi: 10.1006/taap.1994.1158. [DOI] [PubMed] [Google Scholar]
  7. Burbach K. M., Poland A., Bradfield C. A. Cloning of the Ah-receptor cDNA reveals a distinctive ligand-activated transcription factor. Proc Natl Acad Sci U S A. 1992 Sep 1;89(17):8185–8189. doi: 10.1073/pnas.89.17.8185. [DOI] [PMC free article] [PubMed] [Google Scholar]
  8. Carver L. A., Hogenesch J. B., Bradfield C. A. Tissue specific expression of the rat Ah-receptor and ARNT mRNAs. Nucleic Acids Res. 1994 Aug 11;22(15):3038–3044. doi: 10.1093/nar/22.15.3038. [DOI] [PMC free article] [PubMed] [Google Scholar]
  9. Davis A. M., Grattan D. R., Selmanoff M., McCarthy M. M. Sex differences in glutamic acid decarboxylase mRNA in neonatal rat brain: implications for sexual differentiation. Horm Behav. 1996 Dec;30(4):538–552. doi: 10.1006/hbeh.1996.0057. [DOI] [PubMed] [Google Scholar]
  10. Dolwick K. M., Schmidt J. V., Carver L. A., Swanson H. I., Bradfield C. A. Cloning and expression of a human Ah receptor cDNA. Mol Pharmacol. 1993 Nov;44(5):911–917. [PubMed] [Google Scholar]
  11. Ema M., Sogawa K., Watanabe N., Chujoh Y., Matsushita N., Gotoh O., Funae Y., Fujii-Kuriyama Y. cDNA cloning and structure of mouse putative Ah receptor. Biochem Biophys Res Commun. 1992 Apr 15;184(1):246–253. doi: 10.1016/0006-291x(92)91185-s. [DOI] [PubMed] [Google Scholar]
  12. Erlander M. G., Tillakaratne N. J., Feldblum S., Patel N., Tobin A. J. Two genes encode distinct glutamate decarboxylases. Neuron. 1991 Jul;7(1):91–100. doi: 10.1016/0896-6273(91)90077-d. [DOI] [PubMed] [Google Scholar]
  13. Flerkó B., Petrusz P., Tima L. On the mechanism of sexual differentiation of the hypothalamus. Factors influencing the "critical period" of the rat. Acta Biol Acad Sci Hung. 1967;18(1):27–36. [PubMed] [Google Scholar]
  14. Flügge G., Oertel W. H., Wuttke W. Evidence for estrogen-receptive GABAergic neurons in the preoptic/anterior hypothalamic area of the rat brain. Neuroendocrinology. 1986;43(1):1–5. doi: 10.1159/000124500. [DOI] [PubMed] [Google Scholar]
  15. Gao B., Moore R. Y. The sexually dimorphic nucleus of the hypothalamus contains GABA neurons in rat and man. Brain Res. 1996 Dec 2;742(1-2):163–171. doi: 10.1016/s0006-8993(96)01005-0. [DOI] [PubMed] [Google Scholar]
  16. Gorski R. A., Gordon J. H., Shryne J. E., Southam A. M. Evidence for a morphological sex difference within the medial preoptic area of the rat brain. Brain Res. 1978 Jun 16;148(2):333–346. doi: 10.1016/0006-8993(78)90723-0. [DOI] [PubMed] [Google Scholar]
  17. Gray L. E., Jr, Ostby J. S. In utero 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) alters reproductive morphology and function in female rat offspring. Toxicol Appl Pharmacol. 1995 Aug;133(2):285–294. doi: 10.1006/taap.1995.1153. [DOI] [PubMed] [Google Scholar]
  18. Gray L. E., Wolf C., Mann P., Ostby J. S. In utero exposure to low doses of 2,3,7,8-tetrachlorodibenzo-p-dioxin alters reproductive development of female Long Evans hooded rat offspring. Toxicol Appl Pharmacol. 1997 Oct;146(2):237–244. doi: 10.1006/taap.1997.8222. [DOI] [PubMed] [Google Scholar]
  19. Gray L. E., Wolf C., Mann P., Ostby J. S. In utero exposure to low doses of 2,3,7,8-tetrachlorodibenzo-p-dioxin alters reproductive development of female Long Evans hooded rat offspring. Toxicol Appl Pharmacol. 1997 Oct;146(2):237–244. doi: 10.1006/taap.1997.8222. [DOI] [PubMed] [Google Scholar]
  20. Gray P., Brooks P. J. Effect of lesion location within the medial preoptic-anterior hypothalamic continuum on maternal and male sexual behaviors in female rats. Behav Neurosci. 1984 Aug;98(4):703–711. doi: 10.1037//0735-7044.98.4.703. [DOI] [PubMed] [Google Scholar]
  21. Gu Y. Z., Hogenesch J. B., Bradfield C. A. The PAS superfamily: sensors of environmental and developmental signals. Annu Rev Pharmacol Toxicol. 2000;40:519–561. doi: 10.1146/annurev.pharmtox.40.1.519. [DOI] [PubMed] [Google Scholar]
  22. Jacobson C. D., Davis F. C., Gorski R. A. Formation of the sexually dimorphic nucleus of the preoptic area: neuronal growth, migration and changes in cell number. Brain Res. 1985 Jul;353(1):7–18. doi: 10.1016/0165-3806(85)90019-7. [DOI] [PubMed] [Google Scholar]
  23. Lisciotto C. A., Morrell J. I. Sex differences in the distribution and projections of testosterone target neurons in the medial preoptic area and the bed nucleus of the stria terminalis of rats. Horm Behav. 1994 Dec;28(4):492–502. doi: 10.1006/hbeh.1994.1047. [DOI] [PubMed] [Google Scholar]
  24. Mably T. A., Moore R. W., Goy R. W., Peterson R. E. In utero and lactational exposure of male rats to 2,3,7,8-tetrachlorodibenzo-p-dioxin. 2. Effects on sexual behavior and the regulation of luteinizing hormone secretion in adulthood. Toxicol Appl Pharmacol. 1992 May;114(1):108–117. doi: 10.1016/0041-008x(92)90102-x. [DOI] [PubMed] [Google Scholar]
  25. MacLusky N. J., Naftolin F. Sexual differentiation of the central nervous system. Science. 1981 Mar 20;211(4488):1294–1302. doi: 10.1126/science.6163211. [DOI] [PubMed] [Google Scholar]
  26. MacLusky N. J., Philip A., Hurlburt C., Naftolin F. Estrogen formation in the developing rat brain: sex differences in aromatase activity during early post-natal life. Psychoneuroendocrinology. 1985;10(3):355–361. doi: 10.1016/0306-4530(85)90013-7. [DOI] [PubMed] [Google Scholar]
  27. Matsumura F. How important is the protein phosphorylation pathway in the toxic expression of dioxin-type chemicals? Biochem Pharmacol. 1994 Jul 19;48(2):215–224. doi: 10.1016/0006-2952(94)90089-2. [DOI] [PubMed] [Google Scholar]
  28. McDonald P. G., Doughty C. Androgen sterilization in the neonatal female rat and its inhibition by an estrogen antagonist. Neuroendocrinology. 1973;13(3):182–188. doi: 10.1159/000122236. [DOI] [PubMed] [Google Scholar]
  29. McEwen B. S., Lieberburg I., Chaptal C., Krey L. C. Aromatization: important for sexual differentiation of the neonatal rat brain. Horm Behav. 1977 Dec;9(3):249–263. doi: 10.1016/0018-506x(77)90060-5. [DOI] [PubMed] [Google Scholar]
  30. Park O. K., Mayo K. E. Transient expression of progesterone receptor messenger RNA in ovarian granulosa cells after the preovulatory luteinizing hormone surge. Mol Endocrinol. 1991 Jul;5(7):967–978. doi: 10.1210/mend-5-7-967. [DOI] [PubMed] [Google Scholar]
  31. Petersen S. L., Barraclough C. A. Suppression of spontaneous LH surges in estrogen-treated ovariectomized rats by microimplants of antiestrogens into the preoptic brain. Brain Res. 1989 Apr 10;484(1-2):279–289. doi: 10.1016/0006-8993(89)90371-5. [DOI] [PubMed] [Google Scholar]
  32. Petersen S. L., Curran M. A., Marconi S. A., Carpenter C. D., Lubbers L. S., McAbee M. D. Distribution of mRNAs encoding the arylhydrocarbon receptor, arylhydrocarbon receptor nuclear translocator, and arylhydrocarbon receptor nuclear translocator-2 in the rat brain and brainstem. J Comp Neurol. 2000 Nov 20;427(3):428–439. doi: 10.1002/1096-9861(20001120)427:3<428::aid-cne9>3.0.co;2-p. [DOI] [PubMed] [Google Scholar]
  33. Petersen S. L., Gardner E., Adelman J., McCrone S. Examination of steroid-induced changes in LHRH gene transcription using 33P-and 35S-labeled probes specific for intron 2. Endocrinology. 1996 Jan;137(1):234–239. doi: 10.1210/endo.137.1.8536618. [DOI] [PubMed] [Google Scholar]
  34. Petersen S. L., Keller M. L., Carder S. A., McCrone S. Differential effects of estrogen and progesterone on levels of POMC mRNA levels in the arcuate nucleus: relationship to the timing of LH surge release. J Neuroendocrinol. 1993 Dec;5(6):643–648. doi: 10.1111/j.1365-2826.1993.tb00534.x. [DOI] [PubMed] [Google Scholar]
  35. Petersen S. L., LaFlamme K. D. Progesterone increases levels of mu-opioid receptor mRNA in the preoptic area and arcuate nucleus of ovariectomized, estradiol-treated female rats. Brain Res Mol Brain Res. 1997 Dec 1;52(1):32–37. doi: 10.1016/s0169-328x(97)00194-0. [DOI] [PubMed] [Google Scholar]
  36. Pinal C. S., Cortessis V., Tobin A. J. Multiple elements regulate GAD65 transcription. Dev Neurosci. 1997;19(6):465–475. doi: 10.1159/000111244. [DOI] [PubMed] [Google Scholar]
  37. Poland A., Knutson J. C. 2,3,7,8-tetrachlorodibenzo-p-dioxin and related halogenated aromatic hydrocarbons: examination of the mechanism of toxicity. Annu Rev Pharmacol Toxicol. 1982;22:517–554. doi: 10.1146/annurev.pa.22.040182.002505. [DOI] [PubMed] [Google Scholar]
  38. Safe S. H. Comparative toxicology and mechanism of action of polychlorinated dibenzo-p-dioxins and dibenzofurans. Annu Rev Pharmacol Toxicol. 1986;26:371–399. doi: 10.1146/annurev.pa.26.040186.002103. [DOI] [PubMed] [Google Scholar]
  39. Safe S., Wang F., Porter W., Duan R., McDougal A. Ah receptor agonists as endocrine disruptors: antiestrogenic activity and mechanisms. Toxicol Lett. 1998 Dec 28;102-103:343–347. doi: 10.1016/s0378-4274(98)00331-2. [DOI] [PubMed] [Google Scholar]
  40. Silva M. R., Oliveira C. A., Felicio L. F., Nasello A. G., Bernardi M. M. Perinatal treatment with picrotoxin induces sexual, behavioral, and neuroendocrine changes in male rats. Pharmacol Biochem Behav. 1998 May;60(1):203–208. doi: 10.1016/s0091-3057(97)00582-0. [DOI] [PubMed] [Google Scholar]
  41. Simerly R. B., Swanson L. W., Gorski R. A. Reversal of the sexually dimorphic distribution of serotonin-immunoreactive fibers in the medial preoptic nucleus by treatment with perinatal androgen. Brain Res. 1985 Aug 5;340(1):91–98. doi: 10.1016/0006-8993(85)90777-2. [DOI] [PubMed] [Google Scholar]
  42. Simerly R. B., Swanson L. W., Gorski R. A. The distribution of monoaminergic cells and fibers in a periventricular preoptic nucleus involved in the control of gonadotropin release: immunohistochemical evidence for a dopaminergic sexual dimorphism. Brain Res. 1985 Mar 18;330(1):55–64. doi: 10.1016/0006-8993(85)90007-1. [DOI] [PubMed] [Google Scholar]
  43. Simerly R. B., Swanson L. W., Handa R. J., Gorski R. A. Influence of perinatal androgen on the sexually dimorphic distribution of tyrosine hydroxylase-immunoreactive cells and fibers in the anteroventral periventricular nucleus of the rat. Neuroendocrinology. 1985 Jun;40(6):501–510. doi: 10.1159/000124122. [DOI] [PubMed] [Google Scholar]
  44. Sutter T. R., Tang Y. M., Hayes C. L., Wo Y. Y., Jabs E. W., Li X., Yin H., Cody C. W., Greenlee W. F. Complete cDNA sequence of a human dioxin-inducible mRNA identifies a new gene subfamily of cytochrome P450 that maps to chromosome 2. J Biol Chem. 1994 May 6;269(18):13092–13099. [PubMed] [Google Scholar]
  45. Tobet S. A., Hanna I. K. Ontogeny of sex differences in the mammalian hypothalamus and preoptic area. Cell Mol Neurobiol. 1997 Dec;17(6):565–601. doi: 10.1023/A:1022529918810. [DOI] [PMC free article] [PubMed] [Google Scholar]
  46. Varju P., Katarova Z., Madarász E., Szabó G. GABA signalling during development: new data and old questions. Cell Tissue Res. 2001 Aug;305(2):239–246. doi: 10.1007/s004410100356. [DOI] [PubMed] [Google Scholar]
  47. Vizi S., Palfi A., Hatvani L., Gulya K. Methods for quantification of in situ hybridization signals obtained by film autoradiography and phosphorimaging applied for estimation of regional levels of calmodulin mRNA classes in the rat brain. Brain Res Brain Res Protoc. 2001 Aug;8(1):32–44. doi: 10.1016/s1385-299x(01)00082-4. [DOI] [PubMed] [Google Scholar]
  48. Wagner C. K., Nakayama A. Y., De Vries G. J. Potential role of maternal progesterone in the sexual differentiation of the brain. Endocrinology. 1998 Aug;139(8):3658–3661. doi: 10.1210/endo.139.8.6223. [DOI] [PubMed] [Google Scholar]
  49. Whitlock J. P., Jr Induction of cytochrome P4501A1. Annu Rev Pharmacol Toxicol. 1999;39:103–125. doi: 10.1146/annurev.pharmtox.39.1.103. [DOI] [PubMed] [Google Scholar]
  50. Wiegand S. J., Terasawa E. Discrete lesions reveal functional heterogeneity of suprachiasmatic structures in regulation of gonadotropin secretion in the female rat. Neuroendocrinology. 1982 Jun;34(6):395–404. doi: 10.1159/000123335. [DOI] [PubMed] [Google Scholar]

Articles from Environmental Health Perspectives are provided here courtesy of National Institute of Environmental Health Sciences

RESOURCES