Limits...
Glycine receptor in rat hippocampal and spinal cord neurons as a molecular target for rapid actions of 17-beta-estradiol.

Jiang P, Kong Y, Zhang XB, Wang W, Liu CF, Xu TL - Mol Pain (2009)

Bottom Line: Here we show that, in cultured rat hippocampal (HIP) and spinal dorsal horn (SDH) neurons, 17-beta-estradiol (E2) rapidly and reversibly reduced the peak amplitude of whole-cell glycine-activated currents (IGly).Moreover, the E2 effect on IGly persisted in the presence of the calcium chelator BAPTA, the protein kinase inhibitor staurosporine, the classical ER (i.e. ERalpha and ERbeta) antagonist tamoxifen, or the G-protein modulators, favoring a direct action of E2 on GlyRs.In HEK293 cells expressing various combinations of GlyR subunits, E2 only affected the IGly in cells expressing alpha2, alpha2beta or alpha3beta subunits, suggesting that either alpha2-containing or alpha3beta-GlyRs mediate the E2 effect observed in neurons.

View Article: PubMed Central - HTML - PubMed

Affiliation: Institute of Neuroscience and State Key Laboratory of Neuroscience, Chinese Academy of Sciences, Shanghai 200031, PR China.

ABSTRACT
Glycine receptors (GlyRs) play important roles in regulating hippocampal neural network activity and spinal nociception. Here we show that, in cultured rat hippocampal (HIP) and spinal dorsal horn (SDH) neurons, 17-beta-estradiol (E2) rapidly and reversibly reduced the peak amplitude of whole-cell glycine-activated currents (IGly). In outside-out membrane patches from HIP neurons devoid of nuclei, E2 similarly inhibited IGly, suggesting a non-genomic characteristic. Moreover, the E2 effect on IGly persisted in the presence of the calcium chelator BAPTA, the protein kinase inhibitor staurosporine, the classical ER (i.e. ERalpha and ERbeta) antagonist tamoxifen, or the G-protein modulators, favoring a direct action of E2 on GlyRs. In HEK293 cells expressing various combinations of GlyR subunits, E2 only affected the IGly in cells expressing alpha2, alpha2beta or alpha3beta subunits, suggesting that either alpha2-containing or alpha3beta-GlyRs mediate the E2 effect observed in neurons. Furthermore, E2 inhibited the GlyR-mediated tonic current in pyramidal neurons of HIP CA1 region, where abundant GlyR alpha2 subunit is expressed. We suggest that the neuronal GlyR is a novel molecular target of E2 which directly inhibits the function of GlyRs in the HIP and SDH regions. This finding may shed new light on premenstrual dysphoric disorder and the gender differences in pain sensation at the CNS level.

Show MeSH

Related in: MedlinePlus

Interactions of E2 and PGN on IGly. (A) Sample traces illustrating the additive effect of E2 and PGN on IGly. (B) Summary of results from all experiments similar to those shown in A (n = 4–5). Sum (1) is the expected linear summation of the inhibition induced by 10 μM E2 and 1 μM PGN; Sum (2) is the expected linear summation of the inhibition induced by 10 μM E2 and 10 μM PGN. P > 0.05, Unpaired Student's t-test.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
getmorefigures.php?uid=PMC2651124&req=5

Figure 3: Interactions of E2 and PGN on IGly. (A) Sample traces illustrating the additive effect of E2 and PGN on IGly. (B) Summary of results from all experiments similar to those shown in A (n = 4–5). Sum (1) is the expected linear summation of the inhibition induced by 10 μM E2 and 1 μM PGN; Sum (2) is the expected linear summation of the inhibition induced by 10 μM E2 and 10 μM PGN. P > 0.05, Unpaired Student's t-test.

Mentions: A previous study showed that another neurosteroid, pregnanolone (PGN) directly inhibited IGly in a competitive manner [39]. We were interested to know whether E2 and PGN share a common binding site on GlyRs. If the sites are separate, the inhibitory effects should be additive when E2 and PGN were co-applied. As shown in Figure 3A, PGN at 1 μM and 10 μM significantly inhibited the peak amplitude of IGly by 25.1 ± 7.6% and 49.0 ± 5.9% of control, respectively. In the presence of 10 μM E2, additional inhibition of IGly was observed by PGN at both 1 μM (Figure 3B, 51.3 ± 5.3% of control), and 10 μM (Figure 3B, 70.4 ± 7.3% of control). These data suggest that distinct binding sites may mediate the inhibition of E2 and PGN on IGly.


Glycine receptor in rat hippocampal and spinal cord neurons as a molecular target for rapid actions of 17-beta-estradiol.

Jiang P, Kong Y, Zhang XB, Wang W, Liu CF, Xu TL - Mol Pain (2009)

Interactions of E2 and PGN on IGly. (A) Sample traces illustrating the additive effect of E2 and PGN on IGly. (B) Summary of results from all experiments similar to those shown in A (n = 4–5). Sum (1) is the expected linear summation of the inhibition induced by 10 μM E2 and 1 μM PGN; Sum (2) is the expected linear summation of the inhibition induced by 10 μM E2 and 10 μM PGN. P > 0.05, Unpaired Student's t-test.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC2651124&req=5

Figure 3: Interactions of E2 and PGN on IGly. (A) Sample traces illustrating the additive effect of E2 and PGN on IGly. (B) Summary of results from all experiments similar to those shown in A (n = 4–5). Sum (1) is the expected linear summation of the inhibition induced by 10 μM E2 and 1 μM PGN; Sum (2) is the expected linear summation of the inhibition induced by 10 μM E2 and 10 μM PGN. P > 0.05, Unpaired Student's t-test.
Mentions: A previous study showed that another neurosteroid, pregnanolone (PGN) directly inhibited IGly in a competitive manner [39]. We were interested to know whether E2 and PGN share a common binding site on GlyRs. If the sites are separate, the inhibitory effects should be additive when E2 and PGN were co-applied. As shown in Figure 3A, PGN at 1 μM and 10 μM significantly inhibited the peak amplitude of IGly by 25.1 ± 7.6% and 49.0 ± 5.9% of control, respectively. In the presence of 10 μM E2, additional inhibition of IGly was observed by PGN at both 1 μM (Figure 3B, 51.3 ± 5.3% of control), and 10 μM (Figure 3B, 70.4 ± 7.3% of control). These data suggest that distinct binding sites may mediate the inhibition of E2 and PGN on IGly.

Bottom Line: Here we show that, in cultured rat hippocampal (HIP) and spinal dorsal horn (SDH) neurons, 17-beta-estradiol (E2) rapidly and reversibly reduced the peak amplitude of whole-cell glycine-activated currents (IGly).Moreover, the E2 effect on IGly persisted in the presence of the calcium chelator BAPTA, the protein kinase inhibitor staurosporine, the classical ER (i.e. ERalpha and ERbeta) antagonist tamoxifen, or the G-protein modulators, favoring a direct action of E2 on GlyRs.In HEK293 cells expressing various combinations of GlyR subunits, E2 only affected the IGly in cells expressing alpha2, alpha2beta or alpha3beta subunits, suggesting that either alpha2-containing or alpha3beta-GlyRs mediate the E2 effect observed in neurons.

View Article: PubMed Central - HTML - PubMed

Affiliation: Institute of Neuroscience and State Key Laboratory of Neuroscience, Chinese Academy of Sciences, Shanghai 200031, PR China.

ABSTRACT
Glycine receptors (GlyRs) play important roles in regulating hippocampal neural network activity and spinal nociception. Here we show that, in cultured rat hippocampal (HIP) and spinal dorsal horn (SDH) neurons, 17-beta-estradiol (E2) rapidly and reversibly reduced the peak amplitude of whole-cell glycine-activated currents (IGly). In outside-out membrane patches from HIP neurons devoid of nuclei, E2 similarly inhibited IGly, suggesting a non-genomic characteristic. Moreover, the E2 effect on IGly persisted in the presence of the calcium chelator BAPTA, the protein kinase inhibitor staurosporine, the classical ER (i.e. ERalpha and ERbeta) antagonist tamoxifen, or the G-protein modulators, favoring a direct action of E2 on GlyRs. In HEK293 cells expressing various combinations of GlyR subunits, E2 only affected the IGly in cells expressing alpha2, alpha2beta or alpha3beta subunits, suggesting that either alpha2-containing or alpha3beta-GlyRs mediate the E2 effect observed in neurons. Furthermore, E2 inhibited the GlyR-mediated tonic current in pyramidal neurons of HIP CA1 region, where abundant GlyR alpha2 subunit is expressed. We suggest that the neuronal GlyR is a novel molecular target of E2 which directly inhibits the function of GlyRs in the HIP and SDH regions. This finding may shed new light on premenstrual dysphoric disorder and the gender differences in pain sensation at the CNS level.

Show MeSH
Related in: MedlinePlus