en Neurophysiology/Pharmacology Neurophysiology/Pharmacology Experimental research article Experimental research article <p dir="ltr" style="text-align: justify;"><span style="font-size: 12px;"><b>Introduction: </b><font face="Arial,Arial"><font face="Arial,Arial">Retinoid signaling has been argued to have favorable effects on Alzheimer&#39;s disease (AD). We studied the role of chronic intracerebroventricular (ICV) injection of all-trans retinoic acid (ATRA) on the amyloid-beta (A&beta;) model of AD. </font></font></span><span style="font-size: 12px;"><b>Methods: </b><font face="Arial,Arial"><font face="Arial,Arial">Adult male rats weighing 260-330 g were divided into 12 groups of 8 each. Six groups of rats received ATRA (3nM, 30nM, 3&mu;M, 0.3mM, 30mM/rat; ICV) or DMSO 1% (2&mu;l/rat; ICV), bilaterally and in a chronic manner (6 times, twice a week). Forty eight hours following the last injection, memory performance was assessed using a passive avoidance paradigm. One group received A&beta; (10&mu;g/rat; ICV), bilaterally. The control group received DMSO 1% (2&mu;l/rat; ICV). Twenty days later memory performance was assessed. Three groups of rats received A&beta; (10&mu;g/rat; ICV) and then ATRA (3nM or 30nM/rat; ICV) or DMSO 1%, chronically (6 times, twice a week). Another group received DMSO 1% (2&mu;l/rat; ICV) and then, DMSO 1%, chronically (6 times, twice a week). </font></font></span><span style="font-size: 12px;"><b>Results: </b><font face="Arial,Arial"><font face="Arial,Arial">ATRA at doses 0.3mM and 30mM/rat impaired memory retrieval by decreasing step-through latency (STL) and increasing time spent in the dark compartment (TDC), significantly. However, moderate doses (3nM and 30nM/rat) did not change memory performance. ATRA (30nM/rat) increased STL and decreased TDC and NST in the A&beta;-treated rats, significantly compared to the group received A&beta;-DMSO 1%. </font></font></span><span style="font-size: 12px;"><b>Conclusion: </b><font face="Arial,Arial"><font face="Arial,Arial">The results propose a potential prophylactic effect of ATRA in the ICV A&beta; model of AD and indicate the prominence of retinoic acid signaling as a target for AD prevention.</font></font></span></p> All-trans retinoic acid, Alzheimer's disease, Amyloid-β, Rat 34 43 http://ppj.phypha.ir/browse.php?a_code=A-10-796-3&slc_lang=en&sid=1 Siamak Beheshti siamak.beheshti@yahoo.com 3200319475328460017267 3200319475328460017267 Yes Division of Animal Sciences, Department of Biology, Faculty of Sciences, University of Isfahan, Isfahan, Iran Azam Soleimanipour azamsoleimani69@yahoo.com 3200319475328460017268 3200319475328460017268 No Division of Animal Sciences, Department of Biology, Faculty of Sciences, University of Isfahan, Isfahan, Iran