There are two known genes (Crhr1 and Crhr2) coding for CRH receptors, and the interaction of CRH with either receptor can trigger sensitization of DRN neurons thereby leading to a subsequent greater release of serotonin in response to CRH input; this phenomenon may, at least in part, be responsible for the behavioral aberrations associated with depression or anxiety [48]. The gene discussed is CRH; the disease is major depressive disorder.