ABSTRACT
More than sixty one substances have been found in Cannabis sativa which are called cannabinoids. Cannabinoids are involved in all stages of memory.The aim of this study was to evaluate the effects of leaves aquatic extract of Cannabis sativa on the neuronal density of CA1, CA2 and CA3 of Hippocampus in rats. In this experimental study twenty four male Wistar rats [weight 300-350 g] were divided into two experimental and one control groups. Cannabis sativa was extracted with Soxhlet apparatus. Aquatic extract was injected introperitonealy [I.P.] in experimental groups with two dosages [50 mg/kg and 25 mg/kg] for three weeks. After one month, animals were decapitated and their brains were dissected, fixed in 10% formalin, sectioned in 7 micro m thickness and stained by hematoxin-eosin [HE]. By applying dissector techniques and systematic random sampling scheme the neuronal density of CA1, CA2 and CA3 of Hippocampus were estimated. Then, the numerical density in each group compared with control group using t-test and ANOVA statistics and Turkey test by Minitab 13 software. Neuronal density average of CA1 area in control, experimental 1 and 2 groups were 37396 +/- 553, 10081 +/- 233 in CA1 and 10986 +/- 382, CA2 area 33045 +/- 449, 14648 +/- 284 and 17147 +/- 378 and in CA3 area 26324 +/- 437, 10469 +/- 215 and 13829 +/- 359 respectively. Statistical analyses showed significant decrease [P<0.001] in the CA1, CA2 and CA3 of Hippocampus neuronal density in experimental groups compared to control group. Aquatic extract of Cannabis sativa leaves has canabinoids substances that may effectively increase dopamine release and inhibit the production of impulse and induce neuronal degeneration in Hippocampus leading to reduction of the neuronal density of Hippocampus