Abstract:The endocannabinoid system, which widely distributes in the mammalian central nervous system, is involved in regulating a variety of physiological processes and behavioral responses. Cannabinoid receptor 1 (CB1R) is abundantly localized on the neuronal synapse terminals that expresses various receptors of neurotransmitters, such as somatostatin, cholecystokinin, dopamine and serotonin. Activation of CB1R inhibits the release of presynaptic neurotransmitters, and retrogradely controls neuronal excitabilities. However, there are few reports on the expression of CB1R in parvalbumin (PV) positive gamma-aminobutyric acid interneurons in the central nervous system. In this study, immunofluorescence staining and laser confocal imaging techniques were used to identify the PV+ and CB1R+ cell in the hippocampus. We found that a small number of neurons in the hippocampus of male and female CB1R-iCre-EGFP mice were co-expressed with PV and CB1R. Moreover, there was no sex difference of the distribution of PV+/CB1R+ neurons. These results could provide a reference value for further elucidating the functional interaction between PV and CB1R, and also contribute to a more comprehensive understanding of the regulatory role of endocannabinoid system.