Identification and immunohistochemistry of cholinergic and non-cholinergic circular muscle motor neurons in the guinea-pig small intestine

Brookes, Simon J.; Steele, Penelope A.; Costa, M.

doi:10.1016/0306-4522(91)90050-x

Cited by 211 publications

(177 citation statements)

References 44 publications

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“…A later study showed that transmission from descending interneurons to inhibitory motor neurons was largely, if not exclusively, due to fast EPSPs mediated by P2X receptors [5]. Inhibitory motor neurons are immunoreactive for NOS [19] and the great majority of NOS neurons are immunoreactive for P2X 2 receptors [20]. Thus, purinergic transmission from interneurons to inhibitory motor neurons is probably via the P2X 2 subtype.…”

Section: Circuits Regulating Motility Reflexesmentioning

confidence: 98%

Synaptic Transmission at Functionally Identified Synapses in the Enteric Nervous System: Roles for Both Ionotropic and Metabotropic Receptors

Gwynne

Bornstein²

2007

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Digestion and absorption of nutrients and the secretion and reabsorption of fluid in the gastrointestinal tract are regulated by neurons of the enteric nervous system (ENS), the extensive peripheral nerve network contained within the intestinal wall. The ENS is an important physiological model for the study of neural networks since it is both complex and accessible. At least 20 different neurochemically and functionally distinct classes of enteric neurons have been identified in the guinea pig ileum. These neurons express a wide range of ionotropic and metabotropic receptors. Synaptic potentials mediated by ionotropic receptors such as the nicotinic acetylcholine receptor, P2X purinoceptors and 5-HT 3 receptors are seen in many enteric neurons. However, prominent synaptic potentials mediated by metabotropic receptors, like the P2Y 1 receptor and the NK 1 receptor, are also seen in these neurons. Studies of synaptic transmission between the different neuron classes within the enteric neural pathways have shown that both ionotropic and metabotropic synaptic potentials play major roles at distinct synapses within simple reflex pathways. However, there are still functional synapses at which no known transmitter or receptor has been identified. This review describes the identified roles for both ionotropic and metabotropic neurotransmission at functionally defined synapses within the guinea pig ileum ENS. It is concluded that metabotropic synaptic potentials act as primary transmitters at some synapses. It is suggested identification of the interactions between different synaptic potentials in the production of complex behaviours will require the use of well validated computer models of the enteric neural circuitry.

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Section: Circuits Regulating Motility Reflexesmentioning

confidence: 98%

Synaptic Transmission at Functionally Identified Synapses in the Enteric Nervous System: Roles for Both Ionotropic and Metabotropic Receptors

Gwynne

Bornstein²

2007

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“…Overall, P2X 2 R are expressed in both nerve plexuses, in inhibitory motor neurons, IPANs of the myenteric plexus in stomach and intestine, on gastric endings of vagal afferent fibers, VIP noncholinergic secretomotor neurons, and IPANs of the submucous plexus [14]. In contrast to P2X 2 , P2X 3 immunoreactivity in the submucous plexus occurs in most calretinin neurons that represent cholinergic neurons projecting to mucosa or arterioles, and make up~12% of the population [10]; therefore, the activity of some secretomotor neurons is likely to be modulated by P2X 3 receptors in guinea pig. P2X 2 and P2X 3 immunoreactivity was also identified in nerve fibers in enteric ganglia, interganglionic fiber tracts, in the muscularis as well as in the perivascular plexus of the guinea pig gallbladder.…”

Section: Distribution Of Adenosine P2x and P2y Receptors And Gene Pmentioning

confidence: 99%

Purinergic receptors and gastrointestinal secretomotor function

Christofi

2008

Purinergic Signalling

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Secretomotor reflexes in the gastrointestinal (GI) tract are important in the lubrication and movement of digested products, absorption of nutrients, or the diarrhea that occurs in diseases to flush out unwanted microbes. Mechanical or chemical stimulation of mucosal sensory enterochromaffin (EC) cells triggers release of serotonin (5-HT) (among other mediators) and initiates local reflexes by activating intrinsic primary afferent neurons of the submucous plexus. Signals are conveyed to interneurons or secretomotor neurons to stimulate chloride and fluid secretion. Inputs from myenteric neurons modulate secretory rates and reflexes, and special neural circuits exist to coordinate secretion with motility. Cellular components of secretomotor reflexes variably express purinergic receptors for adenosine (A1, A2a, A2b, or A3 receptors) or the nucleotides adenosine 5′-triphosphate (ATP), adenosine diphosphate (ADP), uridine 5′-triphosphate (UTP), or uridine diphosphate (UDP) (P2X 1-7 , P2Y 2 , P2Y 4 , P2Y 6 , P2Y 12 receptors). This review focuses on the emerging concepts in our understanding of purinergic regulation at these receptors, and in particular of mechanosensory reflexes. Purinergic inhibitory (A 1 , A 3 , P2Y 12 ) or excitatory (A 2 , P2Y 1 ) receptors modulate mechanosensitive 5-HT release. Excitatory (P2Y 1 , other P2Y, P2X) or inhibitory (A 1 , A 3 ) receptors are involved in mechanically evoked secretory reflexes or "neurogenic diarrhea." Distinct neural (pre-or postsynaptic) and non-neural distribution profiles of P2X 2 , P2X 3 , P2X 5 , P2Y 1 , P2Y 2 , P2Y 4 , P2Y 6 , or P2Y 12 receptors, and for some their effects on neurotransmission, suggests their role in GI secretomotor function. Luminal A 2b , P2Y 2 , P2Y 4 , and P2Y 6 receptors are involved in fluid and Cl -, HCO 3 -, K + , or mucin secretion. Abnormal receptor expression in GI diseases may be of clinical relevance. Adenosine A 2a or A 3 receptors are emerging as therapeutic targets in inflammatory bowel diseases (IBD) and gastroprotection; they can also prevent purinergic receptor abnormalities and diarrhea. Purines are emerging as fundamental regulators of enteric secretomotor reflexes in health and disease.

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“…The first classes studied were the ascending and descending interneurons and intrinsic sensory neurons. In myenteric ganglia, varicosities belong mostly to these populations [3]. All cell bodies of ascending interneurons are immunoreactive for calretinin and ChAT [4], but just 29 ± 4.8% (n=4) of calretinin-IR varicosities in myenteric ganglia were immunoreactive for VAChT (Fig.…”

Section: Coexistence Of Neuronal Markers In Myenteric Gangliamentioning

confidence: 92%

“…The axons of these neurons are contained mostly in the deep muscular plexus, with some in the circular muscle plexus [4]. All cell bodies of excitatory motorneurons to the circular muscle are ChAT-IR and SP-IR [3]; all inhibitory motorneurons to the circular muscle express immunoreactivity for NOS and VIP in their cell bodies [3]. In the deep muscular plexus, there was almost complete overlap of NOS with VIP and VAChT with SP in varicosities (Fig.…”

Section: Coexistence Of Neuronal Markers In the Deep Muscular Plexusmentioning

confidence: 96%

Neurochemical coding compared between varicose axons and cell bodies of myenteric neurons in the guinea-pig ileum

Sharrad

Chen

Brookes

2013

Neuroscience Letters

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Identification and immunohistochemistry of cholinergic and non-cholinergic circular muscle motor neurons in the guinea-pig small intestine

Cited by 211 publications

References 44 publications

Synaptic Transmission at Functionally Identified Synapses in the Enteric Nervous System: Roles for Both Ionotropic and Metabotropic Receptors

Synaptic Transmission at Functionally Identified Synapses in the Enteric Nervous System: Roles for Both Ionotropic and Metabotropic Receptors

Purinergic receptors and gastrointestinal secretomotor function

Neurochemical coding compared between varicose axons and cell bodies of myenteric neurons in the guinea-pig ileum

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