**Author details**

90 Neuroendocrinology and Behavior

Psychotropic drugs acting on 5-HT receptors, such as AAPDs and 5-HT1A agonists, have been shown to improve social behavior in animals [36; 40; 41]. These results are consistent with the concept that the AVP and 5-HT systems interact both neuroanatomically and neurochemically in the brain areas, e.g. anterior hypothalamus, as demonstrated in Fig. 7 [42]. Therefore, it is reasonable that further research into the neuropeptidergic system, in conjunction with other neurotransmitter/modulator systems, will facilitate the therapeutic strategy for social behavior deficits in patients with schizophrenia and related disorders.

**Figure 7.** Photomicrographs of arginine vasopressin (AVP) and serotonin (5-HT), as revealed by double-labelling immunocytochemistry. Shown are AVP and 5-HT fluorescent immunoreactivity acquired through laser scanning confocal microscopy. The same single optical plane is shown for both neurochemical signals in the top black and white photographs. The combination of both digitized images is shown in color on the top right panel. The AVP is depicted in bright yellow and the 5-HT appears as a red/orange. A volume-rendered data set of serial optical sections through the AVP neuron denoted with the star is shown in the bottom color photograph. The green stippling is 5-HT varicosities and putative synapses clustered around the red-colored AVP neuron (denoted by the star). Scale bars: top, 50 μm; bottom, 30 μm. (Ferris C F et al. *J. Neurosci.* 1997;17:4331-43) (Permission obtained from the

**5. Conclusions** 

Society for Neuroscience)

Tomiki Sumiyoshi\* , Tadasu Matsuoka and Masayoshi Kurachi *Department of Neuropsychiatry, University of Toyama Graduate School of Medicine and Pharmaceutical Sciences, Toyama, Japan* 
