Chronic exposure to anabolic androgenic steroids alters activity and synaptic function in neuroendocrine control regions of the female mouse

Abstract

Summary Disruption of reproductive function is a hallmark of abuse of anabolic androgenic steroids (AAS) in female subjects. To understand the central actions of AAS, patch clamp recordings were made in estrous, diestrous and AAS-treated mice from gonadotropin releasing hormone (GnRH) neurons, neurons in the medial preoptic area (mPOA) and neurons in the anteroventroperiventricular nucleus (AVPV); regions known to provide GABAergic and kisspeptin inputs to the GnRH cells. Action potential (AP) frequency was significantly higher in GnRH neurons of estrous mice than in AAS-treated or diestrous animals. No significant differences in AAS-treated, estrous or diestrous mice were evident in the amplitude or kinetics of spontaneous postsynaptic currents (sPCSs), miniature PSCs or tonic currents mediated by GABAA receptors or in GABAA receptor subunit expression in GnRH neurons. In contrast, the frequency of GABAA receptor-mediated sPSCs in GnRH neurons showed an inverse correlation with AP frequency across the three hormonal states. Surprisingly, AP activity in the medial preoptic area (mPOA), a likely source of GABAergic afferents to GnRH cells, did not vary in concert with the sPSCs in the GnRH neurons. Furthermore, pharmacological blockade of GABAA receptors did not alter the pattern in which there was lower AP frequency in GnRH neurons of AAS-treated and diestrous versus estrous mice. These data suggest that AAS do not impose their effects either directly on GnRH neurons or on putative GABAergic afferents in the mPOA. AP activity recorded from neurons in kisspeptin-rich regions of the anteroventroperiventricular nucleus (AVPV) and the expression of kisspeptin mRNA and peptide did vary coordinately with AP activity in GnRH neurons. Our data demonstrate that AAS treatment imposes a “diestrous-like” pattern of activity in GnRH neurons and suggest that this effect may arise from suppression of presynaptic kisspeptin-mediated excitatory drive arising from the AVPV. The actions of AAS on neuroendocrine regulatory circuits may contribute the disruption of reproductive function observed in steroid abuse.

Corticotropin-Releasing Factor Modulation of Forebrain GABAergic Transmission has a Pivotal Role in the Expression of Anabolic Steroid-Induced Anxiety in the Female Mouse

“…Behavioral testing commenced at BPN55, and treatment with either AAS or oil was continued during testing. AAS treatment imposes an anestrous state characterized by diestras-like profiles (Blasberg and Clark, 1997;Penatti et al, 2009aPenatti et al, , 2011, and control mice were assessed in diestras (Cooper et al, 1993). In some experiments, PN55 diestras female mice that had not received any injections (naïve) were used.…”

“…Coronal brain slices (250-300 mm) were prepared as described (Penatti et al, , 2011. Sections corresponding the dlBnST (Bregma 0.14 mm) or the CeA (Bregma À1.46 mm) were superfused in artificial cerebrospinal fluid (aCSF: 95% O 2 /5% CO 2 saturated aCSF, containing in mM: 125 NaCl, 1.2 CaCl 2 , 10 glucose, 4 KCl, 1 MgCl 2 , 26 NaHCO 3 , 1.25 NaH 2 PO 4 , and 1 ascorbic acid at pH 7.35) for 20 min (1-2 ml aCSF per min) at 22 or 35 1C.…”

“…In some experiments, either 100 mM picrotoxin or 1 mM strychnine (Sigma) were added to the recording bath to block GABA A or glycine receptors, respectively. All physiological data was acquired and stored using a HEKA-EPC9 amplifier (HEKA Instruments, Bellmore, NY, USA) (Penatti et al, 2005(Penatti et al, , 2009a(Penatti et al, , b, 2010(Penatti et al, , 2011.…”

Accelerated Episodic Luteinizing Hormone Release Accompanies Blunted Progesterone Regulation in PCOS-like Female Rhesus Monkeys (Macaca Mulatta) Exposed to Testosterone during Early-to-Mid Gestation

“…The comparable efficacy of NK3 receptor antagonist, ESN364, in diminishing the frequency of episodic LH release in ovariectomized ewes, LH levels in castrated male monkeys, and pre-ovulatory LH surges in female monkeys, reinforces such therapeutic potential [103]. Fetal T exposure has also been shown to alter hypothalamic pre-synaptic glutamate and GABA neuronal inputs to GnRH in both PA female mice [104] and sheep [96]. Increased GABA synaptic connections [43] may enable increased GABA A receptor-mediated drive to GnRH neurons in PA mice [42] likely mediated through depolarization of GnRH neurons [105,106] increasing GnRH release frequency.…”

Bisphenol A enhances kisspeptin neurons in anteroventral periventricular nucleus of female mice

“…Free-floating sections were incubated in 0.5% sodium metaperiodate for 20 min and then in 1% sodium borohydride for 20 min. They were pre-incubated with 1% normal fetal goat serum (blocking solution) for 60 min, and then incubated in rabbit anti-kisspeptin polyclonal antibody (1:1000, Millipore, Billerica, MA, USA) for 24 h at 4 8C as described previously (Penatti et al 2011, Quennell et al 2011. The sections were treated with biotin-conjugated goat antirabbit IgG (1:400; Vector Laboratories, Burlingame, CA, USA) for 2 h at 37 8C.…”