An antagonistic interaction between Galanin (GAL) receptors and Neuropeptide Y Y1 receptors (Y1) has been described in the medulla oblongata and the hypothalamus with physiological implications at cardiovascular level and in food intake. Furthermore GAL increased the Y1 receptor binding in the amygdala.

Aim: 

To obtain a functional behavioural correlate of the GAL/NPY Y1 receptor interactions in the amygdala we have used the open field and the elevated plus maze tests to evaluate anxiety-like behaviour.

Methods: 

Rats (n=6-8) were injected intracerebroventricularly with a threshold dose of GAL (3nmol) and Y1 Leu³¹Pro³⁴NPY(0.1nmol) agonist alone or in combination 15 minutes before the tests. Anxiolytic and locomotor activity parameters were scored in both tests. ANOVA followed by Fisher LSD was used.

Results: 

The coadministration of both peptides significantly increased the time spent (p<0.01) and the number of entries (p<0.001) in the central square in the open field. In the elevated plus maze the percentage of time spent (p<0.01) and the number of entries (p<0.001) in the open arms was also increased after the coadministration of both peptides. GAL and Y1 agonist alone did not change the parameters analyzed. No effect was observed in the locomotor activity by any treatment.

Conclusion: 

These results show that the coinjection of GAL and Y1 agonist induces anxiolytic-like effects suggesting that GAL and NPY system interact to regulate emotional behaviours. These results may give the basis for the development of novel therapeutic drugs targeting GAL and NPY system for treatment of anxiety disorders. Supported by DGCYT(BFI2005-02241) and SEJ(01323).