Tamoxifen alters dopamine output through direct actions upon superfused corpus striatal tissue fragments

Tamoxifen alters dopamine output through direct actions upon superfused corpus striatal tissue fragments

McDermott J L; Anderson L I; Dluzen D E

Neurochemistry International

1998

1998-03

Tamoxifen (10 pg/ml) was infused directly into superfused striatal tissue fragments of ovariectomized rats for a 50 min period. Immediately following the termination of tamoxifen there was a significant increase in dopamine output compared with non-infused controls. No such significant increase was observed with use of a 100 pg/ml tamoxifen dose. Although dopamine output was again increased upon termination of a 2 h infusion of tamoxifen, these levels failed to differ significantly from that of non-infused controls. Similarly, a shorter 10 min duration infusion of tamoxifen failed to alter dopamine output. Finally, we examined whether the tamoxifen-induced, post-infusion increase in dopamine output, as observed following a 50 min infusion of 10 pg/ml, involved a calcium dependent process. To achieve this goal, superfusions were performed with Calcium/Tamoxifen, No Calcium/Tamoxifen, No Calcium/No Tamoxifen and Calcium/No Tamoxifen. A significant increase in dopamine output post-tamoxifen infusion was obtained for the Calcium/Tamoxifen condition compared with the remaining three groups which failed to differ from one another. Taken together these results show that tamoxifen can alter dopamine output through direct, non-genomic effects upon striatal neurons. Responses to this anti-estrogen are intriguing since they are apparent following removal, but not during tamoxifen infusion and represent a calcium-dependent process. These data suggest that tamoxifen may represent an important modulator of nigrostriatal dopaminergic function. (C) 1998 Elsevier Science Ltd. All rights reserved.

breast-cancer; receptor; Biochemistry & Molecular Biology; Neurosciences & Neurology; estrogen; breast-cancer; antagonist; estradiol; nigrostriatal; release; anti-estrogen; antiestrogens; metabolites; brain metastases; sexual-behavior; non-genomic

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