Evaluation of in vivo selective binding of [11C]doxepin to histamine H1 receptors in five animal species

The specific binding of [C-11]doxepin, which has been used as a radioligand for mapping histamine H-1 receptors in human brain by positron emission tomography, was evaluated in five animal species. In mice the [C-11]doxepin uptake was reduced by treatment with cold doxepin and two H-1 receptor antagonists, but not with H-2/H-3 antagonists. The specific binding evaluated with treatment with (+)-chlorpheniramine (H-1 antagonist) was in the range of 10-30% in mouse, rat, rabbit, and monkey, but was not detected in guinea pig. (C) 2004 Elsevier Inc. All rights reserved.