Intraventricular galanin produces a time-dependent modulation of 5-HT1A receptors in the dorsal raphe of the rat

Abstract

Galanin given i.c.v. increased the K(D) values of 5-HT1A receptors in the DR by 100% 10 min after administration. This effect had disappeared 2 h and 5 h after galanin administration. In contrast, i.c.v. galanin caused a 40% increase in the Bmax values at 2 h without affecting the Bmax values 10 min and 5 h after i.c.v. galanin. The mRNA levels of 5-HT1A receptors and of galanin in the DR were significantly decreased by 33% and 56% respectively 2h but not 5h after i.c.v. galanin. These results suggest that in vivo galanin can modulate somatodendritic 5-HT1A receptors in the DR in a time-dependent manner via galanin-5-HT1A receptor interactions. The findings implicate a potential role of galanin in affective disorders.