2. Characteristics of IpaNs-Conti ☆ Sensitivity- Chemosensitivity(化学敏感性) and Mechanosensitivity (机械敏感性) >Chemosensitive Pans V IPANS respond to chemicals, such as inorganic acid and short chain v May be indirect, via 5-HT or ATP Muscle IPAN +Stretch SAC. stretch o channel Aw Contract Muscle SAc Neurite sac Isoprenaline白 Gadolinium e Nicardipine e BK8644
11 2. Characteristics of IPANs- Conti ❖Sensitivity- Chemosensitivity (化学敏感性) and Mechanosensitivity (机械敏感性) ➢Chemosensitive IPANs ✓IPANS respond to chemicals, such as inorganic acid and short chain ✓May be indirect, via 5-HT or ATP SAC, stretch open channel;
> Mucosal mechanoreceptors V Puffs of nitrogen gas on the mucosal induce C-Fos expression in ipan blocked by ttX Unaffected by hexamethonium(六甲铵), the nicotinic receptor antagonist Y Mostly indirect, through the release of 5-HT from enterochromaffin cells(肠嗜铬细胞) in the mucous membrane 粘膜)
12 ➢Mucosal mechanoreceptors: ✓Puffs of nitrogen gas on the mucosal induce C-Fos expression in IPAN ▪Blocked by TTX ▪Unaffected by hexamethonium (六甲铵), the nicotinic receptor antagonist ✓Mostly indirect, through the release of 5-HT from enterochromaffin cells (肠嗜铬细胞) in the mucous membrane (粘膜)
3. Enteric nerve circuits Intrinsic reflexes that affect motility, water and electrolyte secretion and blood flow all occur in the intestine Circuits for motility control Longitudinal Interneuron Circular muscle muscle motor neuron motor neuron ORAL ANAl Intemeuron Network of
13 3. Enteric nerve circuits Intrinsic reflexes that affect motility, water and electrolyte secretion and blood flow all occur in the intestine ❖Circuits for motility control
Secretomotor and vasomotor 2岩 reflexes CM Arteriole LM: longitudinal muscle; MP myenteric plexus; CM: circular Serum ChI electroly muscle; SM: submucosal plexus Muc: mucosa 2. Myenteric intrinsic primary afferent neurons 9. Descending interneurons Absorbed PACAP secretomotor reflex ACh. TK nerved ekstroM coctroytc 11. Submucosal intrinsic primary afferent neurons 2. Non-cholinergic secretomotor/vasodilator neurons 13. Cholinergic secretomotor/vasodilator neurons 14. Cholinergic secretomotor(non-vasodilator )neurons
14 ➢Secretomotor and vasomotor reflexes LM: longitudinal muscle; MP: myenteric plexus; CM: circular muscle; SM: submucosal plexus; Muc: mucosa 2. Myenteric intrinsic primary afferent neurons 9. Descending interneurons: secretomotor reflex 11. Submucosal intrinsic primary afferent neurons 12. Non-cholinergic secretomotor/vasodilator neurons 13. Cholinergic secretomotor/vasodilator neurons 14. Cholinergic secretomotor (non-vasodilator) neurons
II Extrinsic Primary afferent Neurons The rich sensory innervation(神经支配) of the gastrointestinal tract comprise Intrinsic sensory neurons contained entirely within the gastrointestinal wall ☆ Intestinofugal fibres肠离心神经纤维 that project to prevertebral ganglia(椎前神经节) 8 Vagal and spinal afferent that projects to the central nervous system
15 II Extrinsic Primary Afferent Neurons The rich sensory innervation (神经支配) of the gastrointestinal tract comprise: ❖Intrinsic sensory neurons contained entirely within the gastrointestinal wall ❖Intestinofugal fibres 肠离心神经纤维 that project to prevertebral ganglia (椎前神经节) ❖Vagal and spinal afferent that projects to the central nervous system