Autoradiographic localization of 5-CT-insensitive 5-HT1-like recognition sites in guinea pig and rat brain

Quantitative autoradiographic studies, with [3H]5-HT, were used to investigate the distribution of 5-CT-insensitive 5-HT1-like (5-HT1E/1F) recognition sites in rat and guinea pig brain. For comparison and control purposes the distribution of the closely related 5-HT1D binding site, which is abundant in the guinea pig but not the rat, was also investigated, as well as total specific [3H]5-HT binding. Results from this study confirm the previously described regional distribution of the 5-HT1D binding site and also revealed a predominance of 5-CT-insensitive 5-HT1-like 5-HT1E/1F) recognition sites in the olfactory tubercle, caudate putamen, nucleus accumbens and substantia nigra of both species. Interestingly 5-CT-insensitive 5-HT1-like (5-HT1E/1F) recognition sites were particularly dense in the claustrum of the guinea pig, but not the rat.