A relatively recentrly published (1994) technical reference is:
Wisden, Morris (eds.)
"In Situ Hybridization Protocols for the Brain"
Academic Press, San Diego, 1994
144 pp., $37.50 US (Paper Back)
You could also find it interesting to look into:
"PCR in Neuroscience - Methods in Neuroscience Vol. 26"
Academic Press, San Diego, 1995
455 pp., $55 US (Comb Bound)
Aristotle Univ School of Medicine