Hi Xinguo Lu ,

Yes. That might be a general problem with finding interneurons or taking granular DG neurons as one b mistake. Morphological differentiation between GrDGs and interneurons is tricky!

However, the point is that interneurons in DG groups of GABA-like neurons. They use GABA as the main neurotransmitter. Therefore, you may want to use in situ hybridization or just a simpler IHC of GAD65, 67.

You can find different protocols regarding those.

You may also want to examine axon growth and morphological plexi of interneuron axons which are different with other cells in DG.

In some papers, I also have seen that they have been identified and classified by using their neuropeptide or calcium-binding protein content.

But I would recommend using cell-specific viral techniques and electrophysiology to confirm the cells in a coordinate along with patch:

Article Extended Interneuronal Network of the Dentate Gyrus

There are also somatostatin-positive interneurons in the DG:

Article Somatostatin-positive interneurons in the dentate gyrus of m...

Hi Xinguo,

I can understand your pain as I had done that during my PhD and was quite frustrating at times and especially when I was starting. So this is what I used to do:

1. Firstly, we need to have excellent slices as the fast spiking interneurons (FSINs) are very sensitive to oxidative stress or cutting trauma. Do pre incubate your slices at ~ 34-37 C for 10-15 mins before storing them at room temperature.

2. I used to find the dorsal slices ie in which the DG had a sharper 'V shape' better to find FSINs. Further, usually the FSINs used to be located in the border of DG and the hilus. However, you would need to patch and check for the ephys properties to be completely sure.

You may find my paper Article Calcium Permeable AMPA Receptor-Dependent Long Lasting Plast...

Regards,

Debanjan