Neural induction of taste buds

Area of Science:

• Neuroscience
• Developmental Biology
• Sensory Biology

Background:

• Vallate taste buds are innervated by the glossopharyngeal nerve (IXth nerve).
• Bilateral innervation ensures survival of taste buds in adult rats.
• The role of the IXth nerve in taste bud development is not fully understood.

Purpose of the Study:

• To investigate the role of the IXth nerve in the development of vallate taste buds.
• To determine if the IXth nerve is essential for taste bud induction.
• To explore the synergistic interactions between bilateral IXth nerves during development.

Main Methods:

• Surgical removal or crushing of the IXth nerve in neonatal rats at three days old.
• Comparison of taste bud numbers in experimental groups versus controls.
• Analysis of taste bud formation following nerve regeneration.

Main Results:

• Removal of one IXth nerve in neonates profoundly decreased subsequent taste bud development.
• Synergistic interaction between bilateral IXth nerves resulted in more taste buds than predicted.
• Regenerated IXth nerve axons induced significantly more taste buds in the presence of a normal nerve.

Conclusions:

• Vallate taste buds are neurally induced by the IXth nerve.
• Axons of the IXth nerve interact synergistically, rather than competitively, in inducing taste buds.
• Innervated progenitor cells may develop into stem cells, leading to taste bud formation.