Excitatory neurotransmitters in the tentacle flexor muscles responsible for space positioning of the snail olfactory organ

Krajcs, Nóra and Hernádi, László and Elekes, Károly and Kimura, S. and Kiss, Tibor (2014) Excitatory neurotransmitters in the tentacle flexor muscles responsible for space positioning of the snail olfactory organ. INVERTEBRATE NEUROSCIENCE, 14 (1). pp. 59-69. ISSN 1354-2516


Download (1MB) | Preview
[img] Text
Restricted to Repository staff only

Download (1MB) | Request a copy


Recently, three novel flexor muscles (M1, M2 and M3) in the posterior tentacles of the snail have been described, which are responsible for the patterned movements of the tentacles of the snail, Helix pomatia. In this study, we have demonstrated that the muscles received a complex innervation pattern via the peritentacular and olfactory nerves originating from different clusters of motoneurons of the cerebral ganglia. The innervating axons displayed a number of varicosities and established neuromuscular contacts of different ultrastructural forms. Contractions evoked by nerve stimulation could be mimicked by external acetylcholine (ACh) and glutamate (Glu), suggesting that ACh and Glu are excitatory transmitters at the neuromuscular contacts. Choline acetyltransferase and vesicular glutamate transporter immunolabeled axons innervating flexor muscles were demonstrated by immunohistochemistry and in Western blot experiments. Nerve- and transmitter-evoked contractions were similarly attenuated by cholinergic and glutamatergic antagonists supporting the dual excitatory innervation. Dopamine (DA, 10−5 M) oppositely modulated thin (M1/M2) and thick (M3) muscle responses evoked by stimulation of the olfactory nerve, decreasing the contractions of the M1/M2 and increasing those of M3. In both cases, the modulation site was presynaptic. Serotonin (5-HT) at high concentration (10−5 M) increased the amplitude of both the nerve- and the ACh-evoked contractions in all muscles. The relaxation rate was facilitated suggesting pre- and postsynaptic site of action. Our data provided evidence for a DAergic and 5-HTergic modulation of cholinergic nerves innervating flexor muscles of the tentacles as well as the muscles itself. These effects of DA and 5-HT may contribute to the regulation of sophisticated movements of tentacle muscles lacking inhibitory innervation.

Item Type: Article
Uncontrolled Keywords: MODULATION; SEROTONIN; DOPAMINE; GLUTAMATE; ACETYLCHOLINE; Tentacular muscle; olfaction; helix pomatia
Subjects: Q Science / természettudomány > QH Natural history / természetrajz > QH301 Biology / biológia
Depositing User: MTMT SWORD
Date Deposited: 21 Mar 2014 09:08
Last Modified: 01 Apr 2015 23:15

Actions (login required)

Edit Item Edit Item