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Ineffective esophageal motility and the vagus: current challenges and future prospects

View Article: PubMed Central - PubMed

ABSTRACT

Ineffective esophageal motility (IEM) is characterized by low to very low amplitude propulsive contractions in the distal esophagus, hence primarily affecting the smooth muscle part of the esophagus. IEM is often found in patients with dysphagia or heartburn and is commonly associated with gastroesophageal reflux disease. IEM is assumed to be associated with ineffective bolus transport; however, this can be verified using impedance measurements or evaluation of a barium coated marshmallow swallow. Furthermore, water swallows may not assess accurately the motor capabilities of the esophagus, since contraction amplitude is strongly determined by the size and consistency of the bolus. The “peristaltic reserve” of the esophagus can be evaluated by multiple rapid swallows that, after a period of diglutative inhibition, normally give a powerful peristaltic contraction suggestive of the integrity of neural orchestration and smooth muscle action. The amplitude of contraction is determined by a balance between intrinsic excitatory cholinergic, inhibitory nitrergic, as well as postinhibition rebound excitatory output to the musculature. This is strongly influenced by vagal efferent motor neurons and this in turn is influenced by vagal afferent neurons that send bolus information to the solitary nucleus where programmed activation of the vagal motor neurons to the smooth muscle esophagus is initiated. Solitary nucleus activity is influenced by sensory activity from a large number of organs and various areas of the brain, including the hypothalamus and the cerebral cortex. This allows interaction between swallowing activities and respiratory and cardiac activities and allows the influence of acute and chronic emotional states on swallowing behavior. Interstitial cells of Cajal are part of the sensory units of vagal afferents, the intramuscular arrays, and they provide pacemaker activity to the musculature that can generate peristalsis in the absence of innervation. This indicates that a low-amplitude esophageal contraction, observed as IEM, can be caused by a multitude of factors, and therefore many pathways can be potentially explored to restore normal esophageal peristalsis.

No MeSH data available.


Related in: MedlinePlus

Vagal innervation of the smooth muscle esophagus.Notes: The solitary nucleus (or nucleus of the solitary tract) receives sensory input from a wide variety of organs and houses the central pattern generator for the smooth muscle part of the esophagus. The nodose ganglion is a gateway for sensory neurons to the solitary nucleus. It contains the cell bodies of the afferent nerves from the esophagus. The intramuscular arrays are vagal afferent nerve endings that mingle with ICC-IM in the musculature to form sensory units. The intramuscular ICC are likely the pacemaker cells of the esophagus that can generate rhythmic propulsive activity in the absence of innervation. The IGLEs are the vagal afferent nerve endings in the myenteric plexus. EC cells secrete 5-HT upon stimulation that activates vagal sensory neurons. The dorsal motor nucleus of the vagus sends motor neurons to the esophageal body, after receiving central pattern generator information from the solitary nucleus. The cortex/hypothalamus communicates with the solitary nucleus, so that ones acute or chronic emotional state can influence any aspect of swallowing.Abbreviations: 5-HT, 5-hydroxytryptamine, Ach, the neurotransmitter acetylcholine; CPR, central pattern generator; EC, enterochromaffin cells; ICC, interstitial cells of Cajal; IGLEs, intraganglionic laminar endings; IMA, intramuscular array; ICC-IM, intramuscular ICC; M, muscarinic receptor; N, nicotinic synapse; NO, nitric oxide.
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f1-ceg-9-291: Vagal innervation of the smooth muscle esophagus.Notes: The solitary nucleus (or nucleus of the solitary tract) receives sensory input from a wide variety of organs and houses the central pattern generator for the smooth muscle part of the esophagus. The nodose ganglion is a gateway for sensory neurons to the solitary nucleus. It contains the cell bodies of the afferent nerves from the esophagus. The intramuscular arrays are vagal afferent nerve endings that mingle with ICC-IM in the musculature to form sensory units. The intramuscular ICC are likely the pacemaker cells of the esophagus that can generate rhythmic propulsive activity in the absence of innervation. The IGLEs are the vagal afferent nerve endings in the myenteric plexus. EC cells secrete 5-HT upon stimulation that activates vagal sensory neurons. The dorsal motor nucleus of the vagus sends motor neurons to the esophageal body, after receiving central pattern generator information from the solitary nucleus. The cortex/hypothalamus communicates with the solitary nucleus, so that ones acute or chronic emotional state can influence any aspect of swallowing.Abbreviations: 5-HT, 5-hydroxytryptamine, Ach, the neurotransmitter acetylcholine; CPR, central pattern generator; EC, enterochromaffin cells; ICC, interstitial cells of Cajal; IGLEs, intraganglionic laminar endings; IMA, intramuscular array; ICC-IM, intramuscular ICC; M, muscarinic receptor; N, nicotinic synapse; NO, nitric oxide.

Mentions: The amplitude of swallow- and bolus-induced peristaltic contractions is determined by the balance of inhibitory and excitatory neural activities coming from the autonomic and intrinsic nervous systems (Figure 1).16


Ineffective esophageal motility and the vagus: current challenges and future prospects
Vagal innervation of the smooth muscle esophagus.Notes: The solitary nucleus (or nucleus of the solitary tract) receives sensory input from a wide variety of organs and houses the central pattern generator for the smooth muscle part of the esophagus. The nodose ganglion is a gateway for sensory neurons to the solitary nucleus. It contains the cell bodies of the afferent nerves from the esophagus. The intramuscular arrays are vagal afferent nerve endings that mingle with ICC-IM in the musculature to form sensory units. The intramuscular ICC are likely the pacemaker cells of the esophagus that can generate rhythmic propulsive activity in the absence of innervation. The IGLEs are the vagal afferent nerve endings in the myenteric plexus. EC cells secrete 5-HT upon stimulation that activates vagal sensory neurons. The dorsal motor nucleus of the vagus sends motor neurons to the esophageal body, after receiving central pattern generator information from the solitary nucleus. The cortex/hypothalamus communicates with the solitary nucleus, so that ones acute or chronic emotional state can influence any aspect of swallowing.Abbreviations: 5-HT, 5-hydroxytryptamine, Ach, the neurotransmitter acetylcholine; CPR, central pattern generator; EC, enterochromaffin cells; ICC, interstitial cells of Cajal; IGLEs, intraganglionic laminar endings; IMA, intramuscular array; ICC-IM, intramuscular ICC; M, muscarinic receptor; N, nicotinic synapse; NO, nitric oxide.
© Copyright Policy
Related In: Results  -  Collection

License 1 - License 2
Show All Figures
getmorefigures.php?uid=PMC5036831&req=5

f1-ceg-9-291: Vagal innervation of the smooth muscle esophagus.Notes: The solitary nucleus (or nucleus of the solitary tract) receives sensory input from a wide variety of organs and houses the central pattern generator for the smooth muscle part of the esophagus. The nodose ganglion is a gateway for sensory neurons to the solitary nucleus. It contains the cell bodies of the afferent nerves from the esophagus. The intramuscular arrays are vagal afferent nerve endings that mingle with ICC-IM in the musculature to form sensory units. The intramuscular ICC are likely the pacemaker cells of the esophagus that can generate rhythmic propulsive activity in the absence of innervation. The IGLEs are the vagal afferent nerve endings in the myenteric plexus. EC cells secrete 5-HT upon stimulation that activates vagal sensory neurons. The dorsal motor nucleus of the vagus sends motor neurons to the esophageal body, after receiving central pattern generator information from the solitary nucleus. The cortex/hypothalamus communicates with the solitary nucleus, so that ones acute or chronic emotional state can influence any aspect of swallowing.Abbreviations: 5-HT, 5-hydroxytryptamine, Ach, the neurotransmitter acetylcholine; CPR, central pattern generator; EC, enterochromaffin cells; ICC, interstitial cells of Cajal; IGLEs, intraganglionic laminar endings; IMA, intramuscular array; ICC-IM, intramuscular ICC; M, muscarinic receptor; N, nicotinic synapse; NO, nitric oxide.
Mentions: The amplitude of swallow- and bolus-induced peristaltic contractions is determined by the balance of inhibitory and excitatory neural activities coming from the autonomic and intrinsic nervous systems (Figure 1).16

View Article: PubMed Central - PubMed

ABSTRACT

Ineffective esophageal motility (IEM) is characterized by low to very low amplitude propulsive contractions in the distal esophagus, hence primarily affecting the smooth muscle part of the esophagus. IEM is often found in patients with dysphagia or heartburn and is commonly associated with gastroesophageal reflux disease. IEM is assumed to be associated with ineffective bolus transport; however, this can be verified using impedance measurements or evaluation of a barium coated marshmallow swallow. Furthermore, water swallows may not assess accurately the motor capabilities of the esophagus, since contraction amplitude is strongly determined by the size and consistency of the bolus. The “peristaltic reserve” of the esophagus can be evaluated by multiple rapid swallows that, after a period of diglutative inhibition, normally give a powerful peristaltic contraction suggestive of the integrity of neural orchestration and smooth muscle action. The amplitude of contraction is determined by a balance between intrinsic excitatory cholinergic, inhibitory nitrergic, as well as postinhibition rebound excitatory output to the musculature. This is strongly influenced by vagal efferent motor neurons and this in turn is influenced by vagal afferent neurons that send bolus information to the solitary nucleus where programmed activation of the vagal motor neurons to the smooth muscle esophagus is initiated. Solitary nucleus activity is influenced by sensory activity from a large number of organs and various areas of the brain, including the hypothalamus and the cerebral cortex. This allows interaction between swallowing activities and respiratory and cardiac activities and allows the influence of acute and chronic emotional states on swallowing behavior. Interstitial cells of Cajal are part of the sensory units of vagal afferents, the intramuscular arrays, and they provide pacemaker activity to the musculature that can generate peristalsis in the absence of innervation. This indicates that a low-amplitude esophageal contraction, observed as IEM, can be caused by a multitude of factors, and therefore many pathways can be potentially explored to restore normal esophageal peristalsis.

No MeSH data available.


Related in: MedlinePlus