Bimodal Effect of Progesterone on in vitro Dopamine Function of the Rat Corpus striatumDluzen D.E. · Ramirez V.D.
Department of Physiology and Biophysics, University of Illinois, Urbana, Ill.
In the present experiment we examined the temporal effects of progesterone (P) upon in vitro dopamine (DA) release from superfused corpus striatum (CS) and medial basal hypothalami (MBH) tissue fragments. In ovariectomized-estrogen-primed adult female rats, P was systemically administered at 0.5, 2, 4, 12 or 24 h prior to sacrifice for CS and at 4 or 24 h for MBH superfusions. Control groups receiving either steroid alone and/or the oil vehicle were included. Progesterone at the 2- to 12-hour periods stimulated spontaneous and amphetamine-evoked DA release and increased post-superfusion tissue concentrations of DA from the CS when compared to controls. At 24 h P apparently produced an active inhibition, with all parameters of DA activity (spontaneous and AMPH-induced DA release), significantly decreased compared to controls. In contrast, P failed to alter the spontaneous or marginal amphetamine response of the MBH but did significantly reduce post-superfusion DA concentration at 24 h. We hypothesize that the dual effect of P upon brain dopaminergic systems (facilitation followed by inhibition), in the CS but not in the MBH represents changes in DA synthesis and release which are coupled in the CS but not in the MBH.
V.D. Ramirez, Department of Physiology and Biophysics, 524 Burrill Hall, University of Illinois, 407 South Goodwin Avenue, Urbana, lL 61801 (USA)
Received: September 23, 1983
Accepted after revision: January 9, 1984
Published online: March 28, 2008
Number of Print Pages : 7
Neuroendocrinology (International Journal for Basic and Clinical Studies on Neuroendocrine Relationships)
Vol. 39, No. 2, Year 1984 (Cover Date: 1984)
Journal Editor: Millar R.P. (Edinburgh)
ISSN: 0028–3835 (Print), eISSN: 1423–0194 (Online)
For additional information: http://www.karger.com/NEN