To explore the staining methods of primary cilia in cultured rat primary hippocampal neurons, primary culture of 18 day fetal rats′ hippocampal neurons was used in this study. In cellular level，the immunofluorescence staining was used to label the primary cilia of hippocampal neurons at different culture time points and with different antibodies recognizing of different ciliary protein (anti-ADP-ribosylation factor-like protein 13B (ARL13B) antibody，anti-Type III adenylyl cyclase (ACIII) antibody). Fluorescence images were acquired by an inverted fluorescence microscope. From the results, we found that both anti-ARL13B antibodies and anti-ACIII antibodies can label the primary cilia of hippocampal neurons, although anti-ARL13B antibodies with more specific labeling effect. The length of primary cilia increasd during the development of hippocampal neuron cultured in vitro (anti-ACIII antibody groups：the length of primary cilia increases from 21.6 μm at the 1st day to 44.6 μm at the 14th day; anti-ARL13B antibody groups：the length of primary cilia increases from 15.2 μm at the 1st day to 37.6 μm at the 14th day) . The same immunofluorescence experiments

were done in astrocyte with these two antibodies. They can also label the primary cilia of astrocyte. To some

extent, both anti-ARL13B antibodies and anti-ACIII antibodies can act as the marker of the primary cilia in

hippocampal neurons. The primary cilia growed during development of hippocampal neurons cultured in vitro.

Accordingly, primary cilia must play an important role in the development of hippocampal neurons. ARL13B and

ACIII can also act as the marker of the primary cilia of astrocytes.

primary cilia , hippocampal neurons, immunofluorescence, ADP-ribosylation factor-like protein