Precerebellin is the precursor of the brain-specific hexadecapeptide cerebellin, a protein with substantial similarity to the globular region of the B chain of complement component C1q. Cerebellin exerts neuromodulatory functions by directly stimulating norepinephrine release via the adenylate cyclase/pka- dependent signaling pathway; and indirectly enhances adrenocortical secretion in vivo, through a paracrine mechanism involving medullary catecholamine release. The active form of precerebellin is highly enriched in postsynaptic structures of cerebellar Purkinje cells in cartwheel neurons of the dorsal cochlear nucleus. Because precerebellin belongs to the C1q/tumor necrosis factor superfamily of secreted proteins and has similarity to adiponectin and CTRP3, it has been suggested that precerebellin posseses functions other than those already stated.