Present address: Institute of Neuroscience, University of Oregon, Eugene, OR 97403, USA.
Long-term exposure to histamine induces the expression of an embryonic-like motor pattern in an adult nervous system
Article first published online: 14 NOV 2007
European Journal of Neuroscience
Volume 26, Issue 11, pages 3181–3192, December 2007
How to Cite
Sullivan, J. M., Faumont, S., Ducret, E., Le Feuvre, Y., Fénelon, V. S. and Meyrand, P. (2007), Long-term exposure to histamine induces the expression of an embryonic-like motor pattern in an adult nervous system. European Journal of Neuroscience, 26: 3181–3192. doi: 10.1111/j.1460-9568.2007.05944.x
- Issue published online: 16 NOV 2007
- Article first published online: 14 NOV 2007
- Received 23 May 2007, revised 7 October 2007, accepted 15 October 2007
- embryonic motor patterns;
- modulatory neurons;
- neural networks;
- stomatogastric nervous system
Neuromodulatory inputs play important roles in shaping the outputs of neural networks. While the actions of neuromodulatory substances over the short term (seconds, minutes) have been examined in detail, far less is known about the possible longer-term (hours) effects of these substances. To investigate this issue, we used the stomatogastric nervous system (STNS) of the lobster to examine the short- and long-term effects of histamine on rhythmic network activity. The application of histamine to the entire STNS had strong inhibitory effects on all three of the STNS networks, observable within minutes. In contrast, longer-term (> 1 h) application of histamine induced the expression of a single, unified rhythm involving neurons from all three networks. Selective application of histamine to different regions of the STNS demonstrated that a unified rhythm arises following the long-term application of histamine to the commissural ganglia (CoGs; modulatory centres), but not the stomatogastric ganglion (site of neural networks). Strikingly, the single rhythm observed following the long-term application of histamine to the CoGs exhibits many similarities with the single rhythm expressed by the embryonic STNS. Together, these results demonstrate that histamine has markedly different short- and long-term effects on network activity; short-term effects arising through direct actions on the networks and long-term effects mediated by actions on modulatory neurons. Furthermore, they indicate that histamine is able to induce the expression of an embryonic-like rhythm in an adult system, suggesting that long-term actions of histamine may play key roles in the development of the STNS networks.