The animals were divided into six groups: control, vehicle, sham surgery, carnosic acid (CA), Amyloid beta (A��), and carnosic acid + A�� (A�� + CA). Animals in the A�� groups were administered 1.5nm/��L beta-amyloid (1�C40) in the Ca1 region on both sides of the hippocampus. Animals SB203580 msds in the CA groups received 1 mL of CA solution (CA: 10mg/kg) intraperitoneally, 1 hour prior to surgery. This treatment (CA: 3mg/kg) continued a couple of hours after surgery and, subsequently, each afternoon for up to 12 days.2.3. Methods2.3.1. Surgical Procedure Animals were first anesthetized by the intraperitoneal (IP) injection of ketamine (100mg/kg) and xylazine (20mg/kg) and then positioned on a stereotaxic apparatus (Stoelting Co., USA).

The injections were delivered through a 5��L Hamilton syringe at the level of the hippocampus, as following coordinates: antero-posterior, ?3.8mm; lateral, ��2.6mm from bregma and ?2.8mm ventral from the dura. Each injection lasted for 5 minutes, and the needle was kept in place for an additional 5 minutes before being slowly withdrawn.12 days after surgery, behavioral tests were performed on the animals in the animal lab of the Iran University of Medical Sciences.2.3.2. Passive Avoidance Task The passive avoidance task was performed using the shuttle box to study the learning memory status in rats. The shuttle box consists of two equally sized compartments, with a guillotine (execution) door and a grid floor for the delivery of an electric foot shock. An electric light bulb illuminates one compartment, while the other remains in the dark.

During the training session, the animals were individually placed in the light chamber, facing away from the execution door. When the animal entered the darkened compartment, the door was quietly lowered and a 0.5mA foot shock was applied for 2 seconds through the grid floor. During the test session, the animal was placed in the light compartment once more, to enter the dark compartment, but the foot shock was not applied. The latency to step through was recorded [13]. Time latency was recorded up to a maximum of 300 seconds. 2.3.3. Y-Maze Spatial Memory Spontaneous alternation behavior was performed using the Y- maze apparatus to study short-term spatial memory in rats. The Y-maze apparatus, made of gray Plexiglas and covered with a black paper, is shaped like a Y, with three identical arms with an angle of 120�� between each pair of arms [14]. Each arm is 40cm long, 30cm high, and 15cm wide. The arms come together in a central area to form an equilateral triangle that Brefeldin_A is 15cm at its longest axis. Each animal was set out at the end of one arm and was then allowed to move freely inside the maze in an 8-minute session.