I was wondering if anyone had any tricks to do with in situ hybridization in tree shrews as opposed to rats? I've been able to obtain signals using dig-labeled probes on high expressing neuronal markers but am still struggling to obtain signals with low expressing mRNA. One possibility I'm trying out is cutting the slices thinner (10um instead of the 20um commonly used with rats)

Have you thought about increasing your signal with TSA? I used TSA to increase the signal of a low copy dig-dUTP probe. I don't remember what company makes the TSA, but you can use several different labeled antibodies (Fluorescein, HP, etc.). Hope this helps.

Perkin Elmer make TSA

http://las.perkinelmer.com/ApplicationsSummary/Applications/in+situ.htm

If your microtome is good enough you could probably take 5-7 micron slices