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Bizzozzero-Hiriart M, Di Giorgio NP, Libertun C, Lux-Lantos VAR. GABAB Receptor Antagonism from Birth to Weaning Permanently Modifies Kiss1 Expression in the Hypothalamus and Gonads in Mice. Neuroendocrinology 2022; 112:998-1026. [PMID: 34963114 DOI: 10.1159/000521649] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/18/2021] [Accepted: 12/22/2021] [Indexed: 11/19/2022]
Abstract
INTRODUCTION The kisspeptin gene Kiss1 is expressed in two hypothalamic areas: anteroventral periventricular nucleus/periventricular nucleus (AVPV/PeN) and arcuate nucleus (ARC), and also in gonads. Several pieces of evidence suggests that gamma-amino butyric acid B receptors (GABAB) signaling can regulate Kiss1 expression. Here, we inhibited GABAB signaling from PND2 to PND21 and evaluated the hypothalamic-pituitary-gonadal (HPG) axis. METHODS BALB/c mice were treated on postnatal days 2-21 (PND2-PND21) with CGP55845 (GABAB antagonist) and evaluated in PND21 and adulthood: gene expression (qPCR) in the hypothalamus and gonads, hormones by radioimmunoassay, gonad histochemistry (H&E), puberty onset, and estrous cycles. RESULTS At PND21, CGP inhibited Kiss1 and Tac2 and increased Pdyn and Gabbr1 in the ARC of both sexes and decreased Th only in female AVPV/PeN. Serum follicle-stimulating hormone (FSH) and testis weight were decreased in CGP-males, and puberty onset was delayed. In adults, Kiss1, Tac2, Pdyn, Pgr, Cyp19a1, and Gad1 were downregulated, while Gabbr1 was upregulated in the ARC of both sexes. In the AVPV/PeN, Kiss1, Th, Cyp19a1, and Pgr were decreased while Gad1 was increased in CGP-females, whereas Cyp19a1 was increased in CGP-males. Serum FSH was increased in CGP-males while prolactin was increased in CGP-females. Testosterone and progesterone were increased in ovaries from CGP-females, in which Kiss1, Cyp19a1, and Esr1 were downregulated while Hsd3b2 was upregulated, together with increased atretic and decreased ovulatory follicles. Testes from CGP-males showed decreased progesterone, increased Gabbr1, Kiss1, Kiss1r, and Esr2 and decreased Cyp19a1, and clear signs of seminiferous tubules atrophy. CONCLUSION These results demonstrate that appropriate GABAB signaling during this critical prepubertal period is necessary for the normal development of the HPG axis.
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Affiliation(s)
- Marianne Bizzozzero-Hiriart
- Laboratorio de Neuroendocrinología, Instituto de Biología y Medicina Experimental (IBYME-CONICET), Buenos Aires, Argentina
| | - Noelia P Di Giorgio
- Laboratorio de Neuroendocrinología, Instituto de Biología y Medicina Experimental (IBYME-CONICET), Buenos Aires, Argentina
| | - Carlos Libertun
- Laboratorio de Neuroendocrinología, Instituto de Biología y Medicina Experimental (IBYME-CONICET), Buenos Aires, Argentina
- Departamento de Fisiología, Facultad de Medicina, Universidad de Buenos Aires, Buenos Aires, Argentina
| | - Victoria A R Lux-Lantos
- Laboratorio de Neuroendocrinología, Instituto de Biología y Medicina Experimental (IBYME-CONICET), Buenos Aires, Argentina
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Taherianfard M, Bahaddini A, Keshtkar S, Fazeli M, Shomali T. Effect of Extremely Low Frequency Electromagnetic Field and GABAA Receptors on Serum Testosterone Level of Male Rats. Int J Endocrinol Metab 2013; 11:e11029. [PMID: 24719627 PMCID: PMC3968986 DOI: 10.5812/ijem.11029] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/03/2013] [Revised: 07/09/2013] [Accepted: 07/27/2013] [Indexed: 12/01/2022] Open
Abstract
BACKGROUND GABA can influence the steroidogenesis in peripheral and central nervoussystems. OBJECTIVES The present study investigates the interactive effect of GABAA receptors and extremely low frequency electromagnetic field on serum testosterone level of male rats. PATIENTS AND METHODS Fifty adult male rats were randomly assigned into 10 groups. Groups 2, 4, 6, 8, and 10 were exposed to ELF-EMF for 30 days 8hrs per day; while, the remaining groups (1, 3, 5, 7, and 9) were sham exposed animals. At the end of the experiment, animals in groups 1 and 2 received normal saline; while, animals in groups 3 and 4 were treated with 1 mg/kg of bicuculline methiodide, and for animals of groups 5 and 6,3 mg/kg of bicuculline was injected. Animals of groups 7 and 8 were treated with 0.5 mg/kg of muscimol hydrobromide and rats in groups 9 and 10 received 2 mg/kg muscimol hydrobromide. About forty minutes after the injection, blood samples were collected and serum testosterone level was assayed using RIA. RESULTS Administration of muscimol hydrobromide at both doses to sham exposed rats significantly decreased serum testosterone level as compared to sham exposed animals which received saline. Administration of bicuculline methiodide without exposure to ELF-EMF, had no significant effect on testosterone level as compared to group 1. Serum testosterone levels of rats in different groups, exposed to ELF-EMF were statistically the same. Moreover, serum testosterone of exposed and sham exposed rats in each treatment showed no significant difference. CONCLUSIONS No interactivity is present in modulatory effects of GABAA receptors and ELF-EMFs on serum testosterone of male rats.
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Affiliation(s)
- Mahnaz Taherianfard
- Department of Physiology, School of Vetetrinary Medicine, Shiraz University, Shiraz, IR Iran
- Corresponding author: Mahnaz Taherianfard, Department of Physiology, School of Vetetrinary Medicine, Shiraz University, Shiraz, IR Iran. P.O.Box: 1731, Postcode: 71345. Tel: +98-7112286950, Fax: +98-7112286940, E-mail:
| | - Aminolah Bahaddini
- Department of Biology, Faculty of Basic Science, Shiraz University, Shiraz, IR Iran
| | - Sara Keshtkar
- Department of Biology, University of Scientific-Practical, Shiraz University, Shiraz, IR Iran
| | - Mehdi Fazeli
- Department of Pharmacology, School of Vetetrinary Medicine, Shiraz University, Shiraz, IR Iran
| | - Tahora Shomali
- Department of Pharmacology, School of Vetetrinary Medicine, Shiraz University, Shiraz, IR Iran
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Young SZ, Bordey A. GABA's control of stem and cancer cell proliferation in adult neural and peripheral niches. Physiology (Bethesda) 2009; 24:171-85. [PMID: 19509127 PMCID: PMC2931807 DOI: 10.1152/physiol.00002.2009] [Citation(s) in RCA: 99] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Aside from traditional neurotransmission and regulation of secretion, gamma-amino butyric acid (GABA) through GABA(A) receptors negatively regulates proliferation of pluripotent and neural stem cells in embryonic and adult tissue. There has also been evidence that GABAergic signaling and its control over proliferation is not only limited to the nervous system, but is widespread through peripheral organs containing adult stem cells. GABA has emerged as a tumor signaling molecule in the periphery that controls the proliferation of tumor cells and perhaps tumor stem cells. Here, we will discuss GABA's presence as a near-universal signal that may be altered in tumor cells resulting in modified mitotic activity.
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Affiliation(s)
- Stephanie Z Young
- Department of Neurosurgery, Yale University, New Haven, Connecticut, USA
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Tartaglione C, Ritta M. On the presence of 3H-GABA uptake mechanism in bovine spermatozoa. Anim Reprod Sci 2008; 108:247-58. [DOI: 10.1016/j.anireprosci.2007.08.010] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2006] [Accepted: 08/20/2007] [Indexed: 10/22/2022]
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Amikishieva AV. Testosterone and behavior: involvement of the hormone in psychotropic effects of baclofen. Bull Exp Biol Med 2008; 143:259-63. [PMID: 17970216 DOI: 10.1007/s10517-007-0065-3] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
We studied the effect of baclofen (GABA(B) receptor agonist) on the behavior of male mice with different levels of anxiety in tests for social and sexual contact and on blood testosterone levels. The drug reduced testosterone level and behavioral reaction to an unknown male in intact animals and did not modulate the hormone level and social contacts in anxious mice. In the test with receptive female, baclofen reduced testosterone level and sexual motivation in intact males and did not modulate the hormone level and initial sexual interest in anxious mice. Parallelism in the development of behavioral and endocrine components of the reaction to social and sexual stimuli confirms possible involvement of testosterone in psychotropic effects of baclofen.
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Affiliation(s)
- A V Amikishieva
- Institute of Cytology and Genetics, Siberian Division of Russian Academy of Sciences, Novosibirsk.
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Gladkevich A, Korf J, Hakobyan VP, Melkonyan KV. The peripheral GABAergic system as a target in endocrine disorders. Auton Neurosci 2005; 124:1-8. [PMID: 16338174 DOI: 10.1016/j.autneu.2005.11.002] [Citation(s) in RCA: 93] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2005] [Revised: 10/19/2005] [Accepted: 11/01/2005] [Indexed: 12/01/2022]
Abstract
In addition to its well-recognized function as a cerebral inhibitory transmitter, less well established is the role of GABA in peripheral nervous and endocrine systems. We summarize current evidence that GABA serves as a neurotransmitter or neuromodulator in the autonomic nervous system and as a hormone or trophic factor in non-neuronal peripheral tissue as well. GABA is widely distributed in endocrine tissues including the pituitary, pancreas, adrenal glands, uterus, ovaries, placenta and testis. Moreover, GABA is involved in the pathophysiology of endocrine disorders such as diabetes mellitus, diseases of adrenal glands and reproductive tracts. Current literature indicates that the peripheral GABA system in the autonomic nervous system, endocrine and immune systems is as yet nearly an unexplored target for diagnosis and drug treatment.
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Affiliation(s)
- A Gladkevich
- Department of Psychiatry, University Medical Center Groningen, University Groningen, Hanzeplein 1, PO Box 30.001, 9700 RB Groningen, The Netherlands.
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Amikishieva AV, Semendyaeva SN. Effect of diazepam on anxiety, sexual motivation, and blood testosterone in anxious male mice. Bull Exp Biol Med 2005; 140:658-63. [PMID: 16848217 DOI: 10.1007/s10517-006-0047-x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
The effects of diazepam on anxious behavior, sexual motivation, and blood level of testosterone in the presence of a female were studied in male mice with elevated anxiety. Diazepam produced an anxiolytic effect in novel environment, but was ineffective during social contacts. The drug potentiated the primary sexual interest, but failed to correct exhaustion of sexual motivation. The drug produced no effect on blood testosterone.
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Affiliation(s)
- A V Amikishieva
- Institute of Cytology and Genetics, Siberian Division of the Russian Academy of Medical Sciences, Novosibirsk.
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8
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Catalano PN, Bonaventura MM, Silveyra P, Bettler B, Libertun C, Lux-Lantos VA. GABA(B1) knockout mice reveal alterations in prolactin levels, gonadotropic axis, and reproductive function. Neuroendocrinology 2005; 82:294-305. [PMID: 16682806 DOI: 10.1159/000093128] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 12/12/2005] [Indexed: 11/19/2022]
Abstract
gamma-Aminobutyric acid (GABA) has been implicated in the control of hypophyseal functions. We evaluated whether the constitutive loss of functional GABA(B) receptors in GABA(B1) knockout (GABA(B1)(-/-)) mice alters hormonal levels, under basal and stimulated conditions, and reproductive function. The serum hormone levels were measured by radioimmunoassay, the estrous cyclicity was evaluated by vaginal lavages, and the mating behavior was determined by the presence of vaginal plugs. A moderate hyperprolactinemic condition was observed, in which prolactin increase and thyroid-stimulating hormone decrease were similar between genotypes. Basal luteinizing hormone (LH), follicle-stimulating hormone, thyroid-stimulating hormone, and growth hormone levels were similar between genotypes in each sex. Analysis of the gonadotropin axis revealed no differences in puberty onset between female genotypes. In con trast, the estrous cyclicity was significantly disrupted in GABA(B1)(-/-) female mice, showing significantly extended periods in estrus and shortened periods in proestrus. Reproduction was significantly compromised in GABA(B1)(-/-) females, with a significantly lower proportion of mice (37.5%) getting pregnant during the first 30 days of mating as compared with wild-type controls (87.5%). Moreover, only 14% of vaginal plug positive GABA(B1)(-/-) females had successful pregnancies as compared with 75% in the controls. In addition, the postovariectomy LH rise was significantly advanced in GABA(B1)(-/-) mice, while the response to estradiol feedback was similar in both genotypes. In conclusion, our endocrine analysis of GABA(B1)(-/-) mice reveals that GABA(B) receptors are involved in the regulation of basal prolactin titers. Moreover, the hypothalamic-hypophyseal-ovarian axis is seriously disturbed, with alterations in cyclicity, postcastration LH increase, and fertility indexes. The molecular mechanism underlying these hormonal disturbances remains to be addressed.
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Affiliation(s)
- Paolo N Catalano
- Instituto de Biología y Medicina Experimental-CONICET, Universidad de Buenos Aires, Buenos Aires, Argentina
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Ritta MN, Bas DE, Tartaglione CM. In vitro effect of gamma-aminobutyric acid on bovine spermatozoa capacitation. Mol Reprod Dev 2004; 67:478-86. [PMID: 14991740 DOI: 10.1002/mrd.20038] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
Sperm capacitation is defined as the maturational changes that render a sperm competent for fertilization and occurs in the female reproductive tract. Identification of the factor/s that regulate sperm capacitation would allow the understanding of these phenomena. Among these factors, gamma-aminobutyric acid (GABA) has recently become as a putative modulator of sperm function. The aim of this study was to explore the presence of a GABAergic regulation of bovine sperm capacitation as well as the possible intracellular mechanisms involved. GABA was detected in fresh semen by a sensitive radioreceptor assay (spermatozoa, 0.064 +/- 0.003 nmoles/10(6) cells; seminal plasma, 23.21 +/- 1.16 nmoles/ml). Scatchard analysis of [(3)H]-muscimol binding to sperm membranes yielded a linear plot consistent with a single population of binding sites (K(d) = 3.87 nM, B(max) = 417 fmol/mg prot.). [(3)H]-muscimol specific binding to sperm membranes was significantly inhibited by the GABA A receptor (GABA A-R) antagonist bicuculline and by the agonists muscimol and isoguvacine. Addition of GABA to the incubation medium resulted in a concentration-dependent increase in the percentage of capacitated spermatozoa (chlortetracycline assay). We observed a significant increment on intracellular calcium and cyclic 3',5' adenosine monophosphate (cAMP) concentrations induced by GABA, being the cation influx abolished when the cell suspensions were coincubated with the antagonists bicuculline or picrotoxin. It is concluded that GABA induces sperm capacitation through an intracellular mechanism dependent on calcium influx and cAMP accumulation mediated by a specific GABA A-R.
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Affiliation(s)
- M N Ritta
- Institute of Experimental Biology and Medicine, University of Lomas de Zamora, Buenos Aires, Argentina.
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Watanabe M, Maemura K, Kanbara K, Tamayama T, Hayasaki H. GABA and GABA receptors in the central nervous system and other organs. INTERNATIONAL REVIEW OF CYTOLOGY 2002; 213:1-47. [PMID: 11837891 DOI: 10.1016/s0074-7696(02)13011-7] [Citation(s) in RCA: 368] [Impact Index Per Article: 16.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Gamma-aminobutyrate (GABA) is a major inhibitory neurotransmitter in the adult mammalian brain. GABA is also considered to be a multifunctional molecule that has different situational functions in the central nervous system, the peripheral nervous system, and in some nonneuronal tissues. GABA is synthesized primarily from glutamate by glutamate decarboxylase (GAD), but alternative pathways may be important under certain situations. Two types of GAD appear to have significant physiological roles. GABA functions appear to be triggered by binding of GABA to its ionotropic receptors, GABA(A) and GABA(C), which are ligand-gated chloride channels, and its metabotropic receptor, GABA(B). The physiological, pharmacological, and molecular characteristics of GABA(A) receptors are well documented, and diversity in the pharmacologic properties of the receptor subtypes is important clinically. In addition to its role in neural development, GABA appears to be involved in a wide variety of physiological functions in tissues and organs outside the brain.
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Teodorov E, Salzgeber SA, Felicio LF, Varolli FMF, Bernardi MM. Effects of perinatal picrotoxin and sexual experience on heterosexual and homosexual behavior in male rats. Neurotoxicol Teratol 2002; 24:235-45. [PMID: 11943511 DOI: 10.1016/s0892-0362(01)00213-6] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
The effects of perinatal picrotoxin (0.75 mg/kg) on heterosexual and homosexual behavior of male rats, sexually experienced or not, were studied. The following data were obtained: (1) at birth, body weight and anogenital distance were not modified by the treatment; (2) during lactation, both treatment and sex interfered with body weight as well as in adult age; (3) as experimental animals were trained, the heterosexual behavior was improved; (4) picrotoxin treatment reduced lordotic response of homosexual behavior in inexperienced male rats and (5) the heterosexual experience with female rats inhibited homosexual behavior of both experimental and control animals. These results suggest that perinatal maternal picrotoxin exposure improved heterosexual behavior in male rats and the sexual experience reveals this effect. In addition, picrotoxin did not induce feminization in experimental inexperienced rats. Finally, the sexual experience per se promotes changes in brain regions related to male behavioral and sexual aspects.
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Affiliation(s)
- Elizabeth Teodorov
- Department of Pathology, Faculty of Veterinary Medicine and Zootechny, University of São Paulo, Brazil
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Ma YH, Hu JH, Zhou XG, Mei ZT, Fei J, Guo LH. Gamma-aminobutyric acid transporter (GAT1) overexpression in mouse affects the testicular morphology. Cell Res 2000; 10:59-69. [PMID: 10765984 DOI: 10.1038/sj.cr.7290036] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
Gamma-aminobutyric acid and GABAergic receptors were previously reported to be distributed in reproductive systems besides CNS and predicted to participate in the modulation of testicular function. Gamma-aminobutyric acid transporter was implicated to be involved in this process. However, the potential role of gamma-aminobutyric transporter in testis has not been explored. In this study, we investigated the existence of mouse gamma-aminobutyric acid transporter subtype I (mGAT1) in testis. Wild-type and transgenic mice, which overexpressing mGAT1 in a variety of tissues, especially in testis, were primarily studied to approach the profile of mGAT1 in testis. Mice with overexpressed mGAT1 develop normally but with reduced mass and size of testis as compared with wild-type. Testicular morphology of transgenic mice exhibited overt abnormalities including focal damage of the spermatogenic epithelium accompanied by capillaries proliferation and increased diameter of seminiferous tubules lumen. Reduced number of spermatids was also found in some seminiferous tubules. Our results clearly demonstrate the presence of GAT1 in mouse testis and imply that GAT1 is possibly involved in testicular function.
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Affiliation(s)
- Y H Ma
- Shanghai Institute of Cell Biology, Chinese Academy of Science
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Abstract
The receptor subtypes involved in the physiological and pharmacological actions of gamma-amino butyric acid (GABA) in peripheral and endocrine tissues are not clear. Information about the molecular characteristics of GABA(A) receptors in peripheral endocrine tissues is only available for the pancreas and the adrenal medulla. Using reverse transcription (RT) polymerase chain reaction (PCR), the widespread expression of GABA(A) receptors subunits in rat peripheral tissues, including adrenal, ovary, testis, placenta, uterus, and small intestine is shown. It is shown that GABA(A) receptor subunits are expressed in multiple endocrine tissues in a tissue specific manner. These results give an insight into the likely pharmacological properties of these GABA(A) receptors in these tissues. The gonadal endocrine tissues such as the placenta, ovary and the testis express greater range of GABA(A) receptor subunits relative to the adrenal gland. The tissues with greater smooth muscle content, the small intestine and the uterus also express a smaller range of subunits subtypes.
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Affiliation(s)
- M K Akinci
- Garvan Institute of Medical Research, Sydney, NSW, Australia
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Moniz AC, Cruz-Casallas PE, Oliveira CA, Lucisano A, Florio JC, Nicolau AA, Spinosa HS, Bernardi MM. Perinatal fenvalerate exposure: behavioral and endocrinology changes in male rats. Neurotoxicol Teratol 1999; 21:611-8. [PMID: 10492396 DOI: 10.1016/s0892-0362(99)00004-5] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The effects of maternal exposure to fenvalerate during the prenatal and postnatal periods of sexual brain differentiation were studied in adult male offspring. Behavioral (open field, stereotyped, and sexual behaviors), physical (sexual maturation, body and organ weights), endocrine (testosterone levels), and neurochemical (striatal and hypothalamic monoamine and respective metabolite levels) data were assessed. The results showed that there was no change in the age of testis descent or testis weight, nor were there changes in monoamine levels or stereotyped behavior. However, there were significant reductions in ductus deferens and seminal vesicle weights and plasma testosterone concentrations. In addition, treated offspring showed decreased male sexual behavior and increased immobility in the open field. These results indicate that perinatal exposure to fenvalerate during the critical periods of male brain sexual differentiation has long-term effects on the reproductive physiology and behavior of male rats.
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Affiliation(s)
- A C Moniz
- Department of Pathology, Faculty of Veterinary Medicine and Zootechny, University of São Paulo, Brazil
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Silva MR, Oliveira CA, Felicio LF, Nasello AG, Bernardi MM. Perinatal treatment with picrotoxin induces sexual, behavioral, and neuroendocrine changes in male rats. Pharmacol Biochem Behav 1998; 60:203-8. [PMID: 9610943 DOI: 10.1016/s0091-3057(97)00582-0] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
The effects of maternal exposure to picrotoxin (PT) during the prenatal and postnatal periods of sexual brain differentiation were studied. Behavioral (sexual behavior), physical (sexual maturation, body, and organ weights) and neurochemical (striatal and hypothalamic monoamine and respective metabolite levels) data were assessed in the offspring of PT-treated dams. The following results were obtained: 1) sexual maturation as measured by the day of testis descent and testis weight comparison was unchanged; 2) a decrease in male sexual behavior occurred, as well as a decrease in body, ductus deferens, and seminal vesicle weights and in plasma testosterone levels of adult male offspring; 3) striatal dopamine (DA) and homovanillic acid (HVA) levels were decreased and hypothalamic norepinephrine (NE) levels were increased. These results indicate that perinatal exposure to PT during the critical periods of male brain sexual differentiation has long-term effects on the reproductive physiology and behavior of male rats.
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Affiliation(s)
- M R Silva
- Departamento de Farmacologia do Instituto de Ciências Biomédicas, São Paulo, SP, Brasil
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Frungieri MB, Gonzalez-Calvar SI, Calandra RS. Influence of photoinhibition on GABA and glutamic acid levels, and on glutamate decarboxylase activity in the testis and epididymis of the golden hamster. INTERNATIONAL JOURNAL OF ANDROLOGY 1996; 19:171-8. [PMID: 8876267 DOI: 10.1111/j.1365-2605.1996.tb00458.x] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Gamma-aminobutyric acid (GABA) is found in the gonads and accessory reproductive organs, and a direct effect on steroidogenesis and sperm viability and motility has been described. The golden (Syrian) hamster is a seasonal breeder, and a pattern of regression-recrudescence in their reproductive organs is observed when adult animals are exposed to less than 12.5 h daylight for an extended period of time. The purpose of this study was to investigate: (1) the presence of GABA in the testis and epididymis of golden hamsters undergoing regression and spontaneous recrudescence; (2) glutamic acid levels and glutamate decarboxylase (GAD) activity in both tissues, and (3) testicular and epididymal testosterone, dihydrotestosterone and 5 alpha-androstane-3 alpha, 17 beta-diol concentrations. Adult golden hamsters were exposed to long (LP 14L:10D) or short (SP 6L:18D) photoperiods for 9, 12, 14, 16, 18 or 22 weeks. When animals were exposed to SP for 14-16 weeks, the testis and epididymis reached maximal involution. Testicular and epididymal androgen levels showed a marked decrease (p < 0.05) during the regression period, and after 18-22 weeks, values began to recover. Between 12 and 18 weeks in SP, the testicular and epididymal content of GABA and glutamic acid was reduced significantly. The concentration of GABA in both tissues showed a sharp rise (p < 0.05), while the concentration of glutamic acid diminished during the period of maximal involution (p < 0.05). In the testis, GAD activity was increased (p < 0.001) after 14 weeks in SP, with no change in the epididymis. In conclusion, glutamic acid via GAD activity could be the main source of GABA in the testis, but not in the epididymis. Furthermore, the presence of GABA in testicular cells and its subsequent photoperiodic variations might act as an important autocrine and/or paracrine modulatory signal in gonadal processes.
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Affiliation(s)
- M B Frungieri
- Instituto de Biología y Medicina Experimental, Buenos Aires, Argentina
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Frungieri MB, Gonzalez-Calvar SI, Chandrashekar V, Rao JN, Bartke A, Calandra RS. Testicular gamma-aminobutyric acid and circulating androgens in Syrian and Djungarian hamsters during sexual development. INTERNATIONAL JOURNAL OF ANDROLOGY 1996; 19:164-70. [PMID: 8876266 DOI: 10.1111/j.1365-2605.1996.tb00457.x] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Several factors, besides luteinizing hormone (LH), participate in the modulation of testicular function. A number of neurotransmitters are reported to be involved in this process, including a stimulatory action of gamma-aminobutyric acid (GABA) on steroidogenesis in the rat testis. The purpose of this study was to investigate the testicular pattern of GABA and glutamic acid, one of its main precursors, during sexual maturation in two seasonally breeding species: Syrian (golden) and Djungarian hamsters. Plasma androgen levels were also measured. The animals were maintained under long-day photoperiod (16:8, L:D) and were killed at 23, 30, 36, 46, 60, and 90 days of age. A different pattern of developmental changes in body and testicular weight was observed in these two species. GABA was present in the testes at all ages studied. GABA concentration and content showed a sharp elevation in the prepubertal period in golden as well as Djungarian hamsters. However, glutamic acid concentrations remained nearly constant during development in both species. Glutamic acid content increased gradually with age in the golden hamster, while a marked peak at 36 days of age was detected in the Djungarian hamster. Plasma testosterone and dihydrotestosterone levels were maximal at pubertal age in both species. The plasma levels of 5 alpha-androstane-3 alpha, 17 beta-diol increased significantly at 30 days of age in the golden hamster while in Djungarian hamsters this steroid remained unchanged. These results suggest that glutamic acid may serve as a precursor for GABA biosynthesis in the testis. In addition, changes in testicular GABA and plasma androgen levels might reflect a modulatory effect of this neurotransmitter in the acquisition of steroidogenic capability during development.
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Affiliation(s)
- M B Frungieri
- Instituto de Biologia y Medicina Experimental, CONICET, Buenos Aires, Argentina
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Tillakaratne NJ, Erlander MG, Collard MW, Greif KF, Tobin AJ. Glutamate decarboxylases in nonneural cells of rat testis and oviduct: differential expression of GAD65 and GAD67. J Neurochem 1992; 58:618-27. [PMID: 1729406 DOI: 10.1111/j.1471-4159.1992.tb09763.x] [Citation(s) in RCA: 69] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
gamma-Aminobutyric acid (GABA) and its synthetic enzyme, glutamate decarboxylase (GAD), are not limited to the nervous system but are also found in nonneural tissues. The mammalian brain contains at least two forms of GAD (GAD67 and GAD65), which differ from each other in size, sequence, immunoreactivity, and their interaction with the cofactor pyridoxal 5'-phosphate (PLP). We used cDNAs and antibodies specific to GAD65 and GAD67 to study the molecular identity of GADs in peripheral tissues. We detected GAD and GAD mRNAs in rat oviduct and testis. In oviduct, the size of GAD, its response to PLP, its immunoreactivity, and its hybridization to specific RNA and DNA probes all indicate the specific expression of the GAD65 gene. In contrast, rat testis expresses the GAD67 gene. The GAD in these two reproductive tissues is not in neurons but in nonneural cells. The localization of brain GAD and GAD mRNAs in the mucosal epithelial cells of the oviduct and in spermatocytes and spermatids of the testis shows that GAD is not limited to neurons and that GABA may have functions other than neurotransmission.
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Affiliation(s)
- N J Tillakaratne
- Department of Biology, University of California, Los Angeles 90024-1606
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