eating disorders [Naughton et al., 2000; Hoyer et al., 2002; Nichols and Nichols, 2008]. The distribution of 5-HT7 binding sites in discrete areas of the brain, such as the limbic system and thalamocortical regions, overlaps the areas of neuroelectrical activity of theta EROs and suggests a possible role in pathophysiology of affective disorders. Three isoforms have been identified in humans [5-HT7(a), 5-HT7(b), and 5-HT7(d)], encoding proteins varying in the length of their carboxy terminal ends [Heidmann et al., 1997], although no differences have been observed in their signal transduction or tissue distribution [Jasper et al., 1997; Heidmann et al., 1998]. The development of 5-HT7 antagonists [Thomas et al., 2003] and the generation of a Htr7 knockout mouse [Hedlund et al., 2003] have revealed a role for the receptor in the control of circadian rhythms and sleep, as well as in modulating hippocampal neuronal functions such as learning and memory [Hedlund and Sutcliffe, 2004; Roberts et al., 2004; Sprouse et al., 2004; Thomas and Hagan, 2004; Cifariello et al., 2008; Eriksson et al., 2008]. Pharmacologically, 5-HT7 receptors have a high affinity for a number of antidepressants and antipsychotics, such as clozapine and risperidone [Roth et al., 1994], underscoring their potential role
