Abstract: Previously the authors reported on peripheral or central injection ofAVP facilitated memory retention in an inhibitory avoidance (IA) taskin mice. In the present study, we investigated the behavioral effect ofendorgenous vasopressin by using Monoclonal Antibody to [Arg~8] vasopr-essin (AVPMcAb), which was made by another group in the same lab-oratory injected centrally (icy) or peripherally (iv). Male Kunming mice were used in two sets of behavioral experiments,one set was IA task, another was Swimming Test (ST). The retentionlatency (in IA) or percentage of hindlegs immobile time (in ST) wasrespectively recorded as a measure of behavior retention. Results. 1) immediately after IA training, administration (icv)of AVPMcAb (1.5 and 4.5 ng/mouse) impaired retention (p<0.05). 2)AVPMeAb (0.15-1.50 μg/mouse) given iv injection immediately after I Atraining, had no influence on retention (p>0.05). 3) The behavior ret-ention of ST was depressed by AVPMcAb (4.5 ng/mouse) injection(icv). The data suggests that the central but not peripheral endorgenous va-sopressin might have some physiological influence on the animals' memoryfacilitation.

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