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Primary peristalsis in pigeon cervical oesophagus: two EMG patterns
Archives Internationales De Physiologie Et De Biochimie
|October 1, 1984
Summary
Pigeon esophageal peristalsis involves two patterns: simple and complex. Atropine blocks the excitatory component, revealing a distinct, atropine-resistant inhibitory period in the complex pattern.
Area of Science:
- Physiology
- Neuroscience
- Gastroenterology
Background:
- Swallowing triggers distinct electromyographic (EMG) peristaltic patterns in the avian cervical esophagus.
- Two patterns,
- simple
- and
- complex
- , have been identified, differing in their temporal and electrical characteristics.
Purpose of the Study:
- To characterize the neurophysiological mechanisms underlying the simple and complex peristaltic patterns in pigeon cervical esophagus.
- To investigate the role of cholinergic pathways and muscarinic receptors in esophageal motility.
- To differentiate between active and passive inhibitory mechanisms during peristalsis.
Main Methods:
- Electromyography (EMG) was used to record esophageal electrical activity during swallowing in pigeons.
- Pharmacological interventions, specifically atropine administration, were employed to probe the involvement of cholinergic systems.
- Analysis focused on the temporal dynamics, amplitude, and propagation of EMG patterns and their response to pharmacological agents.
Main Results:
- The
- simple
- peristaltic pattern is characterized by a high-amplitude, long-lasting excitatory burst with aboral delay.
- The
- complex
- pattern includes an initial, short, aborally propagating inhibitory period followed by an excitatory burst.
- Atropine abolished the excitatory EMG component of both patterns, while the inhibitory period persisted, exhibiting prolonged duration and reduced propagation speed, indicating an atropine-resistant inhibitory mechanism.
Conclusions:
- The excitatory component of both simple and complex esophageal peristalsis in pigeons is mediated by cholinergic nerves acting on muscarinic receptors.
- The complex pattern possesses an atropine-resistant inhibitory component that is not a passive post-inhibitory rebound, suggesting an active neural inhibitory mechanism.
- These findings elucidate the distinct neural control mechanisms governing different peristaltic patterns in the avian esophagus.