Effect of Intrahippocampal Injection of Aluminum on Active Avoidance Learning in Adult Male Rats

Abstract

Aim of this research was to study the effect of intrahippocampal injection of different doses of AlCl3 in adult male rats on active avoidance learning. Thirty five adult male Wistar rats (250-300 g) were used into five groups: (1) Control, (2) Test-I received daily 1 microL AlCl3 1%, pH = 7.2, 3); Test-II received daily 1 microL AlCl3 0.5%, pH = 3.4, 4); Sham-I received daily 1 microL aCSF, pH = 7.2, 5); Sham-II received daily 1 microL aCSF, pH = 3.4. All rats in test and sham groups treated 10 min before training. Animals were anaesthetized with ketamine HCl/xylazine (90/10 mg kg(-1) b.wt.(-1), i.p.) and underwent a stereotaxic surgery for implant of two stainless steel guide cannula into the hippocampus bilaterally. Every day 10 min after above treatments all rats were used to assess the spatial learning performing using Y-maze. Criterion Correct Response (CCR) was 90% in last session of training. There were no significant differences between training sessions to receiving CCR in control, Sham-I and Sham-II groups. Cognition in animals received AlCl3 1%, pH = 7.2 was impaired significantly with compare to other groups (*p<0.0001). Present results show that intrahippocampal injection of AlCl3 1%, causes active avoidance learning impairment significantly. The exact mechanism of Al3 effect on brain and cognition is remains unknown.