Dynamic modification of oral innervation during metamorphosis in branchiostoma belcheri, the oriental lancelet

Takao Kaji, Keiji Shimizu, Kristin Bruk Artinger, Kinya Yasui

Research output: Contribution to journalArticlepeer-review

6 Citations (Scopus)

Abstract

The oral apparatus in lancelets undergoes a remarkable modification during larval development, especially during metamorphosis, when the oral innervation is radically altered. The larval mouth opens on the left side at the early larval stage, and a peripheral nerve network, the oral nerve ring (ONR), develops around it. The ONR enlarges as the mouth expands caudally, eventually receiving fibers from nerves as far back as the tenth on the left side. The mouth shrinks during metamorphosis, and with this change the ONR regresses; the posterior sixth to tenth nerves become freed from the connection with the ONR, whereas the fourth and fifth nerves retain their connections. This modification is the basis for the asymmetric innervation to the velum. There is no mesodermal or mesenchymal restriction for guiding nerve patterning as typically found in vertebrate cranial nerves. Rather, it seems to be the ONR, which has no counterpart in vertebrates, that plays pivotal roles for patterning the nervous system in the oral region. The oral innervation pattern in lancelets represents a derived character state that may be related to the asymmetry of the ancestral body and head.

Original languageEnglish
Pages (from-to)151-160
Number of pages10
JournalBiological Bulletin
Volume217
Issue number2
DOIs
Publication statusPublished - 2009 Oct

ASJC Scopus subject areas

  • Agricultural and Biological Sciences(all)

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