Involvement of K+channels and calcium-dependent pathways in the action of T3 on amino acid accumulation and membrane potential in Sertoli cells of immature rat testis

Volpato, Karine Cunha; Menegaz, Danusa; Leite, L.; Barreto, Kátia Padilha; Garcia, EA; Silva, Fátima Regina Mena Barreto

doi:10.1016/j.lfs.2003.08.005

Cited by 18 publications

(24 citation statements)

References 23 publications

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“…One µM T 3 increased the in vitro 32 P incorporation into vimentin in 15-day-old rat testis (Zamoner et al, 2005), and elicited membrane hyperpolarization in Sertoli cells (Silva et al, 2001). Otherwise 1 µM T 3 and 0.1 µM T 4 increased amino acid transport and induced changes in the membrane potential in Sertoli cells (Segal 1989;Silva et al, 2001;Volpato et al, 2004).…”

Section: Discussionmentioning

confidence: 96%

“…However, nongenomic actions of TH are now widely described and characterized by rapid responses, since they occur through plasma membrane transport systems (Incerpi et al, 1999b;Davis et al, 2000;Silva et al, 2001;Davis et al, 2002;Silva et al, 2002;Volpato et al, 2004). Although short-term effects of T 4 on actin polymerization have been described in cultured astrocytes (Siegrist-Kaiser et al, 1990) little is known about short-term effects of TH on the activity of the phosphorylating system associated to the IF proteins in the central nervous system of young rats.…”

Section: Discussionmentioning

confidence: 99%

“…These findings led to the identification of nonclassical TH binding elements in the plasma membrane. Through binding to these sites, TH could exert short-term effects, including those on ion fluxes at the plasma membrane (Huang et al, 1999;Incerpi et al, 1999b;Silva et al, 2001;Volpato et al, 2004), on intracellular protein trafficking (Safran et al, 1992;Zhu et al, 1998;Chen et al, 1999), on signal-transducing cytoplasmic kinase activities (Lin et al, 1996(Lin et al, , 1999 and on the cytoskeleton (Siegrist-Kaiser et al, 1990). Also, we reported a rapid nongenomic and Ca 2+ -dependent action of T 3 on the phosphorylating system associated with vimentin in immature rat testes (Zamoner et al, 2005).…”

Section: Introductionmentioning

confidence: 99%

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Short-Term Effects of Thyroid Hormones on Cytoskeletal Proteins Are Mediated by GABAergic Mechanisms in Slices of Cerebral Cortex from Young Rats

et al. 2006

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: Thyroid hormones play important roles in brain function. However, few information is available about the effect of 3,5,3'-triiodo-L-thyronine (T(3)) or thyroxine (T(4)) on the in vitro phosphorylation of intermediate filament (IF) proteins from cerebral cortex of rats. In this study we investigated the involvement of GABAergic mechanisms mediating the effects of T(3) and T(4) on the in vitro incorporation of (32)P into IF proteins from cerebral cortex of 10-day-old male rats. Tissue slices were incubated with or without T(3), T(4), gamma-aminobutiric acid (GABA), kinase inhibitors or specific GABA antagonists and (32)P-orthophosphate for 30 min. The IF-enriched cytoskeletal fraction was extracted in a high salt Triton-containing buffer and the in vitro (32)P incorporation into IF proteins was measured. We first observed that 1 microM T(3) and 0.1 microM T(4) significantly increased the in vitro incorporation of (32)P into the IF proteins studied through the PKA and PKCaMII activities. A similar effect on IF phosphorylation was achieved by incubating cortical slices with GABA. Furthermore, by using specific GABA antagonists, we verified that T(3) induced a stimulatory effect on IF phosphorylation through noncompetitive mechanisms involving GABA(A), beyond GABA(B) receptors. In contrast, T(4) effects were mediated mainly by GABA(B) mechanisms. In conclusion, our results demonstrate a rapid nongenomic action of T(3) and T(4) on the phosphorylating system associated to the IF proteins in slices of cerebral cortex of 10 day-old male rats and point to GABAergic mechanisms mediating such effects.

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Section: Discussionmentioning

confidence: 96%

Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Short-Term Effects of Thyroid Hormones on Cytoskeletal Proteins Are Mediated by GABAergic Mechanisms in Slices of Cerebral Cortex from Young Rats

et al. 2006

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“…Furthermore, previous studies had shown a rapid effect of T 3 on different membrane processes, including amino acid accumulation and membrane potential in Sertoli cells of immature rat testis (Silva et al, 2001;Volpato et al, 2004).…”

Section: Introductionmentioning

confidence: 92%

“…Several evidences in the literature have pointed to the regulation of Sertoli cell IF cytoskeleton by steroid hormones (Show et al, 2003) and thyroid hormones (Paul et al, 1999) and to nongenomic Ca 2+ -dependent mechanisms mediating the effects of thyroid hormones in Sertoli cells (Volpato et al, 2004). Taking into account these findings, we hypothesized that beyond the classical genomic mechanism of action, thyroid hormones elicit rapid nongenomic mechanisms, mediated by Ca 2+ , leading to vimentin reorganization, underlying the cytoskeletal remodeling in immature rat testis.…”

Section: Introductionmentioning

confidence: 99%

Involvement of calcium-dependent mechanisms in T3-induced phosphorylation of vimentin of immature rat testis

et al. 2005

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L‐type voltage‐operated Ca⁺² channels modulate transient Ca⁺² influx triggered by activation of Sertoli cell surface L‐selectin

Kao

Millette

2007

J of Cellular Biochemistry

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Near the base of mammalian seminiferous epithelium, Sertoli cells are joined by tight junctions, which constitute the blood-testis barrier. Differentiating germ cells are completely enveloped by Sertoli cells and must traverse the tight junctions during spermatogenic cycle. Following the specific ligand activation of L-selectin, the up-regulated Rho family small G-proteins have been implicated as important modulators of tight junctional dynamics. Although the activation of L-selectin transmits subsequent intracellular signals in a Ca(+2)-dependent fashion in various cell types, little is understood regarding the signaling pathways utilized by L-selectin in Sertoli cells. Therefore, we have examined the possible resultant calcium influx triggered by specific ligand-activation of cell surface L-selectin receptors or by cross-linking of L-selectin with anti-L-selectin. Spectrofluorimetric studies demonstrate increase of intracellular Ca(+2) levels immediately after the treatment of the L-selectin ligands, fucoidan and sialyl Lewis-a, or after treatment with anti-L-selectin antibody. We then determined the mechanism of Ca(+2) influx by investigating L- and T-type voltage-operated Ca(+2) channels, which have been suggested to present in the membranes of Sertoli cells. Data demonstrate that Sertoli cells treated with L-type voltage-operated Ca(+2) channel antagonists, nifedipine, diltiazem, or verapamil, lead to dose-dependent blockage of L-selectin-induced Ca(+2) influx. Cells treated with mibedradil, a T-type voltage-operated Ca(+2) channel antagonist, results in little or no blocking effect. Therefore, we conclude that activation of Sertoli cell L-selectin induces Ca(+2) influx, which is at least partially regulated by L-type voltage-operated Ca(+2) channels.

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Involvement of K+channels and calcium-dependent pathways in the action of T3 on amino acid accumulation and membrane potential in Sertoli cells of immature rat testis

Cited by 18 publications

References 23 publications

Short-Term Effects of Thyroid Hormones on Cytoskeletal Proteins Are Mediated by GABAergic Mechanisms in Slices of Cerebral Cortex from Young Rats

Short-Term Effects of Thyroid Hormones on Cytoskeletal Proteins Are Mediated by GABAergic Mechanisms in Slices of Cerebral Cortex from Young Rats

Involvement of calcium-dependent mechanisms in T3-induced phosphorylation of vimentin of immature rat testis

L‐type voltage‐operated Ca⁺² channels modulate transient Ca⁺² influx triggered by activation of Sertoli cell surface L‐selectin

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Involvement of K+channels and calcium-dependent pathways in the action of T3 on amino acid accumulation and membrane potential in Sertoli cells of immature rat testis

Cited by 18 publications

References 23 publications

Short-Term Effects of Thyroid Hormones on Cytoskeletal Proteins Are Mediated by GABAergic Mechanisms in Slices of Cerebral Cortex from Young Rats

Short-Term Effects of Thyroid Hormones on Cytoskeletal Proteins Are Mediated by GABAergic Mechanisms in Slices of Cerebral Cortex from Young Rats

Involvement of calcium-dependent mechanisms in T3-induced phosphorylation of vimentin of immature rat testis

L‐type voltage‐operated Ca+2 channels modulate transient Ca+2 influx triggered by activation of Sertoli cell surface L‐selectin

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L‐type voltage‐operated Ca⁺² channels modulate transient Ca⁺² influx triggered by activation of Sertoli cell surface L‐selectin