LINGUAL DEFICITS IN BDNF AND NT3 MUTANT MICE LEADING TO GUSTATORY ANDSOMATOSENSORY DISTURBANCES, RESPECTIVELY

A combination of anatomical, histological and physiological data from wild-type and null-mutated mice have established crucial roles for BDN F and NT3 in gustatory and somatosensory innervation of the tongue, an d indeed for proper development of the papillary surface of the tongue . BDNF in expressed in taste buds, NT3 in many surrounding epithelial structures. Absence of BDNF in mice leads to severely malformed taste bud-bearing papillae and severe reduction of taste buds, a loss of pro per innervation of remaining taste buds and a loss of taste discrimina tion although not of the suckling reflex per se. In contrast, absence if NT3 leads to a massive loss of somatosensory innervation of lingual structures. These findings demonstrate distinct roles for BDNF and NT 3 in the establishment of the complex innervation apparatus of the ton gue with non-overlapping roles for the lingual gustatory and somatosen sory systems. The distinction between different sensory modalities, be ing dependent on either BDNF or NT3 may also have clinical implication s.