Based on these findings and considering the impact of the allosteric receptor protomer interplay in possibly developing new, more rapidly acting antidepressant drugs targeting these heteroreceptor complexes, the current work aimed to gain an improved insight into the possible operation of 5HT1AR-FGFR1 heterocomplexes in the raphe-hippocampal serotonin system under control condition and in a genetic rat model of depression. Here, FGFR1 is linked to major depressive disorder.