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Rich66 · 11-09-2009, 01:13 PM

Did this ever get investigated/confirmed?

J Membr Biol. 2001 May 15;181(2):125-35.
Inhibition of glial Na+ and K+ currents by tamoxifen.

Smitherman KA, Sontheimer H.
Department of Neurobiology and Cell Biology and Medical Scientist Training Program, University of Alabama at Birmingham, Birmingham, AL 35294, USA.
Tamoxifen (tmx) is a non-steroidal triphenylethylene derivative that is predominantly known as a competitive antagonist at the estrogen receptor and is used in the treatment of breast cancer. Recent studies suggest that tamoxifen is also beneficial in the treatment of brain metastases and primary brain tumors. Tmx accumulates in brain and its concentration can be up to 46-fold higher than in serum. Therefore, astrocytes may be exposed to tmx in vivo. We use the whole-cell patch-clamp technique to examine the effects of tmx on voltage-dependent cation currents in rat cortical cultures. Using biophysical and pharmacological methods, we isolate sustained and transient outward potassium currents (I(KS) and I(KT), respectively), inwardly rectifying potassium currents (I(KIR)), and transient inward sodium currents (I(Na)). We show that that TTX-sensitive I(Na) is completely inhibited by 10 microm tmx within 5 min. Similarly, tmx blocks I(KS), but does not inhibit I(KT) or I(KIR) at these concentrations. Tmx effects are irreversible with 10 min wash. Interestingly, the currents sensitive to tmx are important in growth control of glial cellsincubation with tmx significantly reduces cell proliferation as examined by 3[H]-thymidine uptake (MacFarlane & Sontheimer, 1997). Therefore, we examine cytotoxic and proliferative effects of tmx. Tmx (10 microm) is not cytotoxic as judged by trypan blue exclusion. However, .

PMID: 11420599 [PubMed - indexed for MEDLINE]

11-09-2009, 01:13 PM	#8
Rich66 Senior Member Join Date: Feb 2008 Location: South East Wisconsin Posts: 3,431	Re: Tamoxifen (ER+, ER-, synergies etc) Did this ever get investigated/confirmed? J Membr Biol. 2001 May 15;181(2):125-35. Inhibition of glial Na+ and K+ currents by tamoxifen. Smitherman KA, Sontheimer H. Department of Neurobiology and Cell Biology and Medical Scientist Training Program, University of Alabama at Birmingham, Birmingham, AL 35294, USA. Tamoxifen (tmx) is a non-steroidal triphenylethylene derivative that is predominantly known as a competitive antagonist at the estrogen receptor and is used in the treatment of breast cancer. Recent studies suggest that tamoxifen is also beneficial in the treatment of brain metastases and primary brain tumors. Tmx accumulates in brain and its concentration can be up to 46-fold higher than in serum. Therefore, astrocytes may be exposed to tmx in vivo. We use the whole-cell patch-clamp technique to examine the effects of tmx on voltage-dependent cation currents in rat cortical cultures. Using biophysical and pharmacological methods, we isolate sustained and transient outward potassium currents (I(KS) and I(KT), respectively), inwardly rectifying potassium currents (I(KIR)), and transient inward sodium currents (I(Na)). We show that that TTX-sensitive I(Na) is completely inhibited by 10 microm tmx within 5 min. Similarly, tmx blocks I(KS), but does not inhibit I(KT) or I(KIR) at these concentrations. Tmx effects are irreversible with 10 min wash. Interestingly, the currents sensitive to tmx are important in growth control of glial cellsincubation with tmx significantly reduces cell proliferation as examined by 3[H]-thymidine uptake (MacFarlane & Sontheimer, 1997). Therefore, we examine cytotoxic and proliferative effects of tmx. Tmx (10 microm) is not cytotoxic as judged by trypan blue exclusion. However, . PMID: 11420599 [PubMed - indexed for MEDLINE] __________________ Mom's treatment history (link)