Cyclic AMP is one of the bioactive components in the extract of Fructus Jujubae

which is reported to be involved with the treatment of depression. To investigate the content of cAMP in the plasma and hippocampus according to the time variation after a single administration of the extract orally at the dose of 0.35 g ·kg-1 in mice

the plasma and hippocampi were collected at the time of 0.5

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12 and 24 h and the ELISA method is used to determine the content of cAMP. As a result

the content of cAMP in plasma reaches to the maximum at the 0.5 h

and then decreases gradually from the 0.5 h to the 8 h. However

the content reversely increases rapidly from the 8 h to the 12 h

while decreases again in the following 12 hours. As to the hippocampi

differences are significant. The cAMP content in hippocampi is ascending gently in the first 6 hours and increasing quickly in the following hours. It is an indication that some bioactive substances in the extract of Fructus Jujubae are likely to be the specific inhibitor of Phosphodiesterase type Ⅳ (PDE4). Therefore

the extract treated to the mice can inhibit the activity of PDE4 and increase the content of cAMP in the plasma and hippocampi during the time of 6 to 12 h. Thus

a possible mechanism for the antidepressant like effect of the extract of Fructus Jujubae is involved with the inhibition of PDE4.