Buccal neurons activate ciliary beating in the foregut of the pteropod molluskClione limacina

Abstract

SUMMARYBeating of cilia lining the foregut of gastropods facilitates the swallowing of food and, therefore, plays a role in feeding behavior. Despite the fact that neural control of feeding is well studied in mollusks, no neurons controlling ciliary beating in the foregut have been identified to date. Here we describe for the first time a pair of buccal neurons innervating the foregut of Clione. Intracellular stimulation of these neurons induced vigorous activation of cilia lining the foregut in a semi-intact preparation. Using immunochemistry labeling, buccal foregut cells were found to contain peptides similar to CNP neuropeptides of the terrestrial snail Helix lucorum. Application of DYPRL-amide, a member of the Helix CNP peptide family, mimicked the effect of buccal foregut cell stimulation on ciliary activity. Induction of fictive feeding in an isolated CNS preparation resulted in the activation of buccal foregut cells suggesting that these cells control ciliary beating in the foregut during feeding. Thus, cilia-activating buccal neurons may represent a new intrinsic element of the neural control of feeding in gastropods.

Dopamine suppresses neuronal activity of Helisoma B5 neurons via a D2-like receptor, activating PLC and K channels

“…A brief inhibition of the N1a activity by hyperpolarizing current injection resets the phase of the fictive feeding pattern. Studies on the Helisoma B5 neuron (Murphy and Kater, 1980), as well as in its homologs in Lymnaea (Perry et al, 1998) and Clione (Malyshev and Balaban, 2009), indicate that these neurons extend axons via the ipsilateral esophageal trunk nerve (Helisoma) and dorsobuccal nerves (Lymnaea) and project to the surface of the proesophagus. Experiments using an isolated foregut preparation reveal that manipulations of the neuronal activity of Lymnaea B2 neurons changed the tension of esophageal muscles (Perry et al, 1998).…”

“…B5 neurons in Helisoma, like their homologs in the closely-related species Lymnaea and Clione, innervate the esophagus and are involved in feeding behavior (Perry et al, 1998;Malyshev and Balaban, 2009). Excitation of the neurons in Lymnaea leads to contraction of the foregut, while their silencing results in relaxation (Perry et al, 1998).…”

The neuronal control of cardiac functions in Molluscs

“…the CNP-and enkaphalin-like peptides. The immunoreactivity to CNP-like peptide is shown in left cerebral (two neurons), right cerebral (2), left pleural (1), left buccal (1), and right buccal (1) ganglia of Clione (Malyshev and Balaban, 2009). The [Met5]-enkaphalin-like peptide was found in VD1 and RPD2 neurons and the neural terminals in atrium of Lymnaea (Ewadinger et al, 1996).…”