CRH-R1 and CRH-R2 differentially modulate dendritic outgrowth of hippocampal neurons

Corticotropin-releasing hormone (CRH) has been implicated to be involved in the development of dendrites in brain. In the present study, we examined the effect of CRH on dendrite outgrowth in primary cultured hippocampal neurons and defined the specific CRH receptor subtype involved. Treatment of neurons with increasing concentration of CRH resulted in an increase in the total dendritic branch length (TDBL) of neurons compared with untreated neurons over 2-4 days period of treatment. These effects can be reversed by the specific CRH-R1 antagonist antalarmin but not by the CRH-R2 antagonist astressin 2B. Treatment of neurons with urocortin II, the exclusive CRH-R2 agonist, significantly decreased TDBL of the cultured neurons. These effects can be reversed by the CRH-R2 antagonist astressin 2B. Our results suggest that CRH-R1 and CRH-R2 differentially modulate the dendritic growth of hippocampal neurons in culture.