Direct neuronal interactions between the duodenum and the sphincter of Oddi

Current gastroenterology reports

Volumn 2, Issue 2, 2000, Pages 104-111

  Kennedy, A L ^a   Saccone, G T ^a   Mawe, G M ^a  

^a BRIDGEWATER STATE UNIVERSITY   (United States)

Author keywords

[No Author keywords available]

Indexed keywords

CHOLECYSTOKININ;

AUTONOMIC NERVOUS SYSTEM; BILE; DUODENUM; GALLBLADDER; HUMAN; INNERVATION; ODDI SPHINCTER; PHYSIOLOGY; POSTPRANDIAL STATE; REVIEW;

AUTONOMIC NERVOUS SYSTEM; BILE; CHOLECYSTOKININ; DUODENUM; GALLBLADDER; HUMANS; POSTPRANDIAL PERIOD; SPHINCTER OF ODDI;

EID: 0034168976     PISSN: 15228037     EISSN: None     Source Type: Journal    
DOI: 10.1007/s11894-000-0093-x     Document Type: Review

References (45)

1. 1. EK Talmage K Hillsley AL Kennedy 1997 Identification of the cholinergic neurons in guinea pig sphincter of Oddi ganglia J Auton Nerv Sys 64 12 18 10.1016/S0165-1838(97)00009-X 1:CAS:528:DyaK2sXislegurc%3D This paper demonstrates that a distinct subpopulation of guinea pig SO neurons is cholinergic, and that the remaining neurons are nitrergic. These data indicate that SO ganglia, unlike gallbladder ganglia, are comprised of separate groups of neurons that can mediate excitatory or inhibitory neurotransmission Talmage EK, Hillsley K, Kennedy AL, et al.: Identification of the cholinergic neurons in guinea pig sphincter of Oddi ganglia. J Auton Nerv Sys 1997, 64:12–18. This paper demonstrates that a distinct subpopulation of guinea pig SO neurons is cholinergic, and that the remaining neurons are nitrergic. These data indicate that SO ganglia, unlike gallbladder ganglia, are comprised of separate groups of neurons that can mediate excitatory or inhibitory neurotransmission.
2. 2. DG Wells EK Talmage GM Mawe 1995 Immunohistochemical identification of neurons in ganglia of the guinea pig sphincter of Oddi J Comp Neurol 352 106 116 7536219 10.1002/cne.903520108 1:STN:280:DyaK2M3ivF2ktw%3D%3D Wells DG, Talmage EK, Mawe GM: Immunohistochemical identification of neurons in ganglia of the guinea pig sphincter of Oddi. J Comp Neurol 1995, 352:106–116.
3. 3. ME Simula ACB Meedeniya J Toouli 1999 Projection and neurochemical coding of circular muscle motor neurons innervating the sphincter of Oddi (SO) in the Australian possum Neurogastroenterol Motil 11 291 291 Simula ME, Meedeniya ACB, Toouli J, et al.: Projection and neurochemical coding of circular muscle motor neurons innervating the sphincter of Oddi (SO) in the Australian possum. Neurogastroenterol Motil 1999, 11:291.
4. 4. MR Cox RTA Padbury JR Harvey 1998 Substance P stimulates sphincter of Oddi motility and inhibits trans-sphincteric flow in the Australian brush-tailed possum Neurogastroenterol Motil 10 165 173 9614675 1:STN:280:DyaK1c3ns1ymuw%3D%3D This report from a possum study describes the distribution of substance P immunoreactivity in the extrahepatic biliary tree and demonstrates that exogenous substance P stimulates SO motility, which results in a reduction in trans-sphincteric flow. These effects of substance P were tetrodotoxin-insensitive, suggesting that substance P acts directly on the SO smooth muscle Cox MR, Padbury RTA, Harvey JR, et al.: Substance P stimulates sphincter of Oddi motility and inhibits trans-sphincteric flow in the Australian brush-tailed possum. Neurogastroenterol Motil 1998, 10:165–173. This report from a possum study describes the distribution of substance P immunoreactivity in the extrahepatic biliary tree and demonstrates that exogenous substance P stimulates SO motility, which results in a reduction in trans-sphincteric flow. These effects of substance P were tetrodotoxin-insensitive, suggesting that substance P acts directly on the SO smooth muscle.
5. 5. CGA Persson M Ekman 1972 Effect of morphine, cholecystokinin and sympathomimetics on the sphincter of Oddi and intramural pressure in cat duodenum Scand J Gastroenterol 7 345 351 5048749 1:CAS:528:DyaE38XltV2gtLg%3D 10.3109/00365527209180753 Persson CGA, Ekman M: Effect of morphine, cholecystokinin and sympathomimetics on the sphincter of Oddi and intramural pressure in cat duodenum. Scand J Gastroenterol 1972, 7:345–351.
6. 6. C Dahlstrand R Edin A Dahlstrom 1985 An in vivo model for the simultaneous study of motility of the gallbladder, sphincter of Oddi and duodenal wall in the cat Acta Physiol Scand 123 355 362 2414975 1:STN:280:DyaL28%2FkslWrsg%3D%3D Dahlstrand C, Edin R, Dahlstrom A, et al.: An in vivo model for the simultaneous study of motility of the gallbladder, sphincter of Oddi and duodenal wall in the cat. Acta Physiol Scand 1985, 123:355–362.
7. 7. C Dahlstrand S Bjorck R Edin 1988 Substance P in the control of extrahepatic biliary motility in the cat Regul Pept 20 11 24 2451260 10.1016/0167-0115(88)90053-5 1:CAS:528:DyaL1cXovVCgtw%3D%3D Dahlstrand C, Bjorck S, Edin R, et al.: Substance P in the control of extrahepatic biliary motility in the cat. Regul Pept 1988, 20:11–24.
8. 8. DG Wells GM Mawe 1993 Physiological and morphological properties of neurons in the sphincter of Oddi region of the guinea pig Am J Physiol 265 G258 G269 8368309 1:CAS:528:DyaK3sXmsVKksbs%3D Wells DG, Mawe GM: Physiological and morphological properties of neurons in the sphincter of Oddi region of the guinea pig. Am J Physiol 1993, 265:G258-G269.
9. 9. C Dahlstrand A Dahlström E Theodorsson 1990 Is the CCK-8 induced relaxation of the feline sphincter of Oddi mediated by VIP neurons? J Auton Nerv Syst 31 75 84 2262668 10.1016/0165-1838(90)90174-H 1:CAS:528:DyaK3MXit1Wksbo%3D Dahlstrand C, Dahlström A, Theodorsson E, et al.: Is the CCK-8 induced relaxation of the feline sphincter of Oddi mediated by VIP neurons? J Auton Nerv Syst 1990, 31:75–84.
10. 10. JW Wiley TM O’Dorisio C Owyang 1988 Vasoactive intestinal polypeptide mediates cholecystokinin-induced relaxation of the sphincter of Oddi J Clin Invest 81 1920 1924 3384954 1:CAS:528:DyaL1cXksVyrt74%3D Wiley JW, O’Dorisio TM, Owyang C: Vasoactive intestinal polypeptide mediates cholecystokinin-induced relaxation of the sphincter of Oddi. J Clin Invest 1988, 81:1920–1924.
11. 11. HS Kaufman MA Shermak CA May 1993 Nitric oxide inhibits resting sphincter of Oddi activity Am J Surg 165 74 80 7678190 10.1016/S0002-9610(05)80407-6 1:CAS:528:DyaK3sXhsVChtLc%3D Kaufman HS, Shermak MA, May CA, et al.: Nitric oxide inhibits resting sphincter of Oddi activity. Am J Surg 1993, 165:74–80.
12. 12. JG Pauletzki KA Sharkey JS Davison 1993 Involvement of L-arginine-nitric oxide pathways in neural relaxation of the sphincter of Oddi Eur J Parmacol 232 263 270 10.1016/0014-2999(93)90783-E 1:CAS:528:DyaK3sXhvVCiurc%3D Pauletzki JG, Sharkey KA, Davison JS, et al.: Involvement of L-arginine-nitric oxide pathways in neural relaxation of the sphincter of Oddi. Eur J Parmacol 1993, 232:263–270.
13. 13. J Behar P Biancani 1980 The effect of cholecystokinin and the octapeptide of cholecystokinin on the feline sphincter of Oddi and gallbladder J Clin Invest 66 1231 239 7440712 1:CAS:528:DyaL3MXktFykug%3D%3D Behar J, Biancani P: The effect of cholecystokinin and the octapeptide of cholecystokinin on the feline sphincter of Oddi and gallbladder. J Clin Invest 1980, 66:1231–239.
14. 14. RA Baker GT Saccone SJ Brookes 1993 Nitric oxide mediates nonadrenergic, noncholinergic neural relaxation in the Australian possum Gastroenterology 105 1746 53 7902822 1:CAS:528:DyaK2cXltFSmtw%3D%3D Baker RA, Saccone GT, Brookes SJ, et al.: Nitric oxide mediates nonadrenergic, noncholinergic neural relaxation in the Australian possum. Gastroenterology 1993, 105:1746–53.
15. 15. Saccone GTP, Simula ME, Brookes SJH, et al.: Distribution of nitric oxide synthase immunoreactivity in the possum sphincter of Oddi myenteric plexus. In Neurogastroenterology, Falk Symposium 112. Edited by Singer MV, Kramer H-J. Lancaster: Klewer Academic Publishers; 2000.
16. 16. HD Allescher S Lu EE Daniel 1993 Nitric oxide as putative nonadrenergic noncholinergic inhibitory transmitter in the opossum sphincter of Oddi Can J Physiol Pharmacol 71 525 530 7902198 1:CAS:528:DyaK3sXms1eitLc%3D Allescher HD, Lu S, Daniel EE: Nitric oxide as putative nonadrenergic noncholinergic inhibitory transmitter in the opossum sphincter of Oddi. Can J Physiol Pharmacol 1993, 71:525–530.
17. 17. TM Lin GF Spray 1969 Effect of pentagastrin, cholecystokinin (CCK), caerulein and glucagon on the choledochal resistance and bile flow of the conscious dog Gastroenterol 56 1178 1178 Lin TM, Spray GF: Effect of pentagastrin, cholecystokinin (CCK), caerulein and glucagon on the choledochal resistance and bile flow of the conscious dog. Gastroenterol 1969, 56:1178.
18. 18. JE Geenen WJ Hogan WJ Dodds 1980 Intraluminal pressure recording from the human sphincter of Oddi Gastroenterology 78 317 324 7350055 1:STN:280:DyaL3c%2FntVWltA%3D%3D Geenen JE, Hogan WJ, Dodds WJ, et al.: Intraluminal pressure recording from the human sphincter of Oddi. Gastroenterology 1980, 78:317–324.
19. 19. J Toouli WJ Hogan JE Geenen 1982 Action of cholecystokinin-octapeptide on sphincter of Oddi basal pressure and phasic wave activity in humans Surgery 92 497 503 6287657 1:CAS:528:DyaL38XlvFenu70%3D Toouli J, Hogan WJ, Geenen JE, et al.: Action of cholecystokinin-octapeptide on sphincter of Oddi basal pressure and phasic wave activity in humans. Surgery 1982, 92:497–503.
20. 20. J Behar P Biancani 1987 Pharmacologic characterization of excitatory and inhibitory cholecystokinin receptors of the cat gallbladder and sphincter of Oddi Gastroenterology 92 764 770 3817397 1:CAS:528:DyaL2sXktFyitLY%3D Behar J, Biancani P: Pharmacologic characterization of excitatory and inhibitory cholecystokinin receptors of the cat gallbladder and sphincter of Oddi. Gastroenterology 1987, 92:764–770.
21. 21. Woods C, Schloithe A, Simula M, et al.: Proximal and distal segments of the possum sphincter of Oddi respond differently to cholecystokinin octapeptide in vitro. Dig Surg 2000, in press.
22. 22. KL Cox Schrenck T Von TH Moran 1990 Characterization of cholecystokinin receptors on the sphincter of Oddi Am J Physiol 259 G873 G881 2240227 1:CAS:528:DyaK3MXjs1ehsw%3D%3D Cox KL, Von Schrenck T, Moran TH, et al.: Characterization of cholecystokinin receptors on the sphincter of Oddi. Am J Physiol 1990, 259:G873-G881.
23. 23. N Hanyu WJ Dodds RD Layman 1990 Cholecystokinininduced contraction of opossum sphincter of Oddi Dig Dis Sci 35 567 576 1970534 10.1007/BF01540403 1:CAS:528:DyaK3MXisVSqu78%3D Hanyu N, Dodds WJ, Layman RD, et al.: Cholecystokinininduced contraction of opossum sphincter of Oddi. Dig Dis Sci 1990, 35:567–576.
24. 24. K Harrington A Bomzon KA Sharkey 1992 Differential sensitivities of the sphincter of Oddi and gallbladder to cholecystokinin in the guinea pig: their role in transsphincteric bile flow Can J Physiol Pharmacol 70 1336 1341 1362689 1:CAS:528:DyaK3sXht1Si Harrington K, Bomzon A, Sharkey KA, et al.: Differential sensitivities of the sphincter of Oddi and gallbladder to cholecystokinin in the guinea pig: their role in transsphincteric bile flow. Can J Physiol Pharmacol 1992, 70:1336–1341.
25. 25. F Vogalis RAR Bywater GS Taylor 1989 Propulsive activity of the isolated choledochoduodenal junction of the guinea pig J Gastroenterol Motil 1 115 121 10.1111/j.1365-2982.1989.tb00149.x Vogalis F, Bywater RAR, Taylor GS: Propulsive activity of the isolated choledochoduodenal junction of the guinea pig. J Gastroenterol Motil 1989, 1:115–121.
26. 26. AP Gokin K Hillsley GM Mawe 1997 Cholecystokinin (CCK) depolarizes guinea pig sphincter of Oddi neurons by activating CCK-A receptors Am J Physiol 272 G1365 G1371 9227471 1:CAS:528:DyaK2sXktlKntbs%3D The results of this study demonstrate that, although guinea pig SO neurons are sensitive to CCK, the concentrations of CCK that are necessary to activate SO neurons are orders of magnitude higher than the circulating concentrations of CCK after a meal. These findings indicate that hormonal CCK is unlikely to mediate the CCK-induced changes in motor activity that are observed in the SO following a meal Gokin AP, Hillsley K, Mawe GM: Cholecystokinin (CCK) depolarizes guinea pig sphincter of Oddi neurons by activating CCK-A receptors. Am J Physiol 1997, 272:G1365-G1371. The results of this study demonstrate that, although guinea pig SO neurons are sensitive to CCK, the concentrations of CCK that are necessary to activate SO neurons are orders of magnitude higher than the circulating concentrations of CCK after a meal. These findings indicate that hormonal CCK is unlikely to mediate the CCK-induced changes in motor activity that are observed in the SO following a meal.
27. 27. T Takahashi D May C Owyang 1991 Cholinergic dependence of gallbladder response to cholecystokinin in the guinea pig in vitro Am J Physiol 261 G565 G569 1681736 1:CAS:528:DyaK3MXmsVyntL8%3D Takahashi T, May D, Owyang C: Cholinergic dependence of gallbladder response to cholecystokinin in the guinea pig in vitro. Am J Physiol 1991, 261:G565-G569.
28. 28. GM Mawe MD Gershon 1989 Structure, afferent innervation, and transmitter content of ganglia of the guinea pig gallbladder: relationship to the enteric nervous system J Comp Neurol 283 374 390 2568371 10.1002/cne.902830306 1:STN:280:DyaL1MzgvFeitg%3D%3D Mawe GM, Gershon MD: Structure, afferent innervation, and transmitter content of ganglia of the guinea pig gallbladder: relationship to the enteric nervous system. J Comp Neurol 1989, 283:374–390.
29. 29. RTA Padbury JB Furness RA Baker 1993 Projections of nerve cells from the duodenum to the sphincter of Oddi and gallbladder of the Australian possum Gastroenterology 104 130 136 8419235 1:STN:280:DyaK3s7it1Cntw%3D%3D Padbury RTA, Furness JB, Baker RA, et al.: Projections of nerve cells from the duodenum to the sphincter of Oddi and gallbladder of the Australian possum. Gastroenterology 1993, 104:130–136.
30. 30. AL Kennedy GM Mawe 1998 Duodenal sensory neurons project to sphincter of Oddi ganglia in guinea pig J Neurosci 18 8065 8073 9742173 1:CAS:528:DyaK1cXmtlequ7k%3D This study provides conclusive evidence for a duodenum-SO neural circuit in the guinea pig. Furthermore, results of this study demonstrate that the SO-duodenum circuit includes a contingent of intrinsic primary afferent neurons of the duodenal myenteric plexus, and that these neurons can be activated by CCK Kennedy AL, Mawe GM: Duodenal sensory neurons project to sphincter of Oddi ganglia in guinea pig. J Neurosci 1998, 18:8065–8073. This study provides conclusive evidence for a duodenum-SO neural circuit in the guinea pig. Furthermore, results of this study demonstrate that the SO-duodenum circuit includes a contingent of intrinsic primary afferent neurons of the duodenal myenteric plexus, and that these neurons can be activated by CCK.
31. 31. ME Simula ACB Meedeniya J Toouli 1998 Distribution of myenteric neurons projecting to the sphincter of Oddi in the Australian brush-tailed possum Proc Aust Physiol Pharmacol Soc 29 208P 208P Simula ME, Meedeniya ACB, Toouli J, et al.: Distribution of myenteric neurons projecting to the sphincter of Oddi in the Australian brush-tailed possum. Proc Aust Physiol Pharmacol Soc 1998, 29:208P.
32. 32. SJH Brookes PA Steele M Costa 1991 Calretinin immunoreactivity in cholinergic motor neurones, interneurones and vasomotor neurones in the guinea pig small intestine Cell Tissue Res 263 471 481 1715238 10.1007/BF00327280 1:STN:280:DyaK3MzksleitA%3D%3D Brookes SJH, Steele PA, Costa M: Calretinin immunoreactivity in cholinergic motor neurones, interneurones and vasomotor neurones in the guinea pig small intestine. Cell Tissue Res 1991, 263:471–481.
33. 33. WAA Kunze JC Bornstein JB Furness 1995 Identification of sensory nerve cells in a peripheral organ (the intestine) of a mammal Neuroscience 66 1 4 7637860 10.1016/0306-4522(95)00067-S 1:CAS:528:DyaK2MXls1ShsLY%3D Kunze WAA, Bornstein JC, Furness JB: Identification of sensory nerve cells in a peripheral organ (the intestine) of a mammal. Neuroscience 1995, 66:1–4.
34. 34. N Clerc JB Furness ZS Li 1998 Morphological and immuno-histochemical identification of neurons and their targets in the guinea-pig duodenum Neuroscience 86 679 694 9881879 10.1016/S0306-4522(98)00025-6 1:CAS:528:DyaK1cXktlGgurk%3D This study represents the first thorough investigation of the neurons of the duodenum and their projection patterns. One of the many findings is that, as in the ileum, neurons that are immunoreactive for calbindin send processes to the mucosa. These neurons are primary sensory neurons, and a contingent send processes to the SO. Therefore, a single neuron is capable of detecting the release of CCK from the mucosa and providing a signal to the SO Clerc N, Furness JB, Li ZS, et al.: Morphological and immuno-histochemical identification of neurons and their targets in the guinea-pig duodenum. Neuroscience 1998, 86:679–694. This study represents the first thorough investigation of the neurons of the duodenum and their projection patterns. One of the many findings is that, as in the ileum, neurons that are immunoreactive for calbindin send processes to the mucosa. These neurons are primary sensory neurons, and a contingent send processes to the SO. Therefore, a single neuron is capable of detecting the release of CCK from the mucosa and providing a signal to the SO.
35. 35. Z-M Song SHJ Brookes M Costa 1994 All calbindin-immunoreactive myenteric neurons project to the mucosa of guinea-pig small intestine Neurosci Lett 180 219 222 7535407 10.1016/0304-3940(94)90524-X 1:CAS:528:DyaK2MXhsValsrk%3D Song Z-M, Brookes SHJ and Costa M: All calbindin-immunoreactive myenteric neurons project to the mucosa of guinea-pig small intestine. Neurosci Lett 1994, 180:219–222.
36. 36. JB Furness DC Trussell S Pompola 1990 Calbindin neurons of the guinea-pig small intestine: quantitative analysis of their numbers and projections Cell Tissue Res 260 261 272 2357722 10.1007/BF00318629 1:CAS:528:DyaK3cXksFKhsLo%3D Furness JB, Trussell DC, Pompola S, et al.: Calbindin neurons of the guinea-pig small intestine: quantitative analysis of their numbers and projections. Cell Tissue Res 1990, 260:261–272.
37. 37. V Iyer JC Bornstein M Costa 1988 Electrophysiology of guinea-pig myenteric neurons correlated with immunoreactivity for calcium binding proteins J Auton Nerv Syst 22 141 150 3379251 10.1016/0165-1838(88)90087-2 1:CAS:528:DyaL1cXktVCntbs%3D Iyer V, Bornstein JC, Costa M et al.: Electrophysiology of guinea-pig myenteric neurons correlated with immunoreactivity for calcium binding proteins. J Auton Nerv Syst 1988, 22:141–150.
38. 38. AL Kennedy GM Mawe 1999 Duodenal neurons provide nicotinic synaptic input to sphincter of Oddi neurons in guinea pig Am J Physiol 277 G226 G234 10409171 This study demonstrates that neurons in the duodenal myenteric plexus provide nicotinic, fast excitatory synaptic input to the neurons of the SO, and that these inputs can be activated at the level of the duodenal mucosa, indicating that this circuit could conduct information regarding the release of signal agents, such as CCK, from the epithelium. Results of this study also indicate that the duodenum-SO neural circuit is a two-way street because electrophysiologic and axonal tracing data demonstrate that SO neurons project to the duodenum Kennedy AL, Mawe GM: Duodenal neurons provide nicotinic synaptic input to sphincter of Oddi neurons in guinea pig. Am J Physiol 1999, 277:G226-G234. This study demonstrates that neurons in the duodenal myenteric plexus provide nicotinic, fast excitatory synaptic input to the neurons of the SO, and that these inputs can be activated at the level of the duodenal mucosa, indicating that this circuit could conduct information regarding the release of signal agents, such as CCK, from the epithelium. Results of this study also indicate that the duodenum-SO neural circuit is a two-way street because electrophysiologic and axonal tracing data demonstrate that SO neurons project to the duodenum.
39. 39. K Hillsley GM Mawe 1998 5-HT is present in nerves of guinea pig sphincter of Oddi and depolarizes sphincter of Oddi neurons Am J Physiol 275 G1018 G1027 9815032 1:STN:280:DyaK1M%2Fjt1Kgug%3D%3D This study demonstrates that serotonergic nerve fibers are abundant in SO ganglia and that serotonin activates SO neurons by causing a depolarization and an increase in excitability. Although some of the serotonergic nerves are apparently intrinsic to the SO, it is possible that the remaining serotonergic axons are a contingent of the duodenum-SO projection Hillsley K, Mawe GM: 5-HT is present in nerves of guinea pig sphincter of Oddi and depolarizes sphincter of Oddi neurons. Am J Physiol 1998, 275:G1018-G1027. This study demonstrates that serotonergic nerve fibers are abundant in SO ganglia and that serotonin activates SO neurons by causing a depolarization and an increase in excitability. Although some of the serotonergic nerves are apparently intrinsic to the SO, it is possible that the remaining serotonergic axons are a contingent of the duodenum-SO projection.
40. 40. J Behar P Biancani 1983 Neural control of the sphincter of Oddi: a physiological role for 5-hydroxytryptamine in the regulation of basal sphincter of Oddi motor activity in the cat J Clin Invest 72 551 559 6874956 1:CAS:528:DyaL3sXltFKktr0%3D 10.1172/JCI111003 Behar J, Biancani P: Neural control of the sphincter of Oddi: a physiological role for 5-hydroxytryptamine in the regulation of basal sphincter of Oddi motor activity in the cat. J Clin Invest 1983, 72:551–559.
41. 41. AP Wyatt 1967 The relationship of the sphincter of Oddi to the stomach, duodenum and gallbladder J Physiol (Lond) 193 225 243 1:STN:280:DyaF1c%2FovVOrsg%3D%3D Wyatt AP: The relationship of the sphincter of Oddi to the stomach, duodenum and gallbladder. J Physiol (Lond) 1967, 193:225–243.
42. 42. A Thune L Jivegård J Svanvik 1989 Flow resistance in the feline choledocho-duodenal sphincter as studied by constant-pressure and constant-perfusion techniques Acta Physiol Scand 135 279 284 2929367 1:STN:280:DyaL1M7ovF2ntg%3D%3D 10.1111/j.1748-1716.1989.tb08578.x Thune A, Jivegård L, Svanvik J: Flow resistance in the feline choledocho-duodenal sphincter as studied by constant-pressure and constant-perfusion techniques. Acta Physiol Scand 1989, 135:279–284.
43. 43. ME Simula JR Harvey D Costi 1997 In vitro characterisation of intramural neural pathways between the duodenum and the sphincter of Oddi of the brush-tailed possum J Auton Nerv Syst 63 77 84 9089542 10.1016/S0165-1838(96)00135-X 1:STN:280:DyaK2s3ksVOltA%3D%3D This in vitro study demonstrates the presence of an intrinsic neural pathway between the duodenum and the SO. Electrical activation of duodenal nerves evoked an excitatory response in the SO. The neural mediation of this response was confirmed by loss of the response following nerve disruption by tissue crushing or blockade with tetrodotoxin. The response was inhibited by atropine and hexamethonium, indicating that a cholinergic component is part of the pathway. A small adrenergic component may also be present Simula ME, Harvey JR, Costi D, et al.: In vitro characterisation of intramural neural pathways between the duodenum and the sphincter of Oddi of the brush-tailed possum. J Auton Nerv Syst 1997, 63:77–84. This in vitro study demonstrates the presence of an intrinsic neural pathway between the duodenum and the SO. Electrical activation of duodenal nerves evoked an excitatory response in the SO. The neural mediation of this response was confirmed by loss of the response following nerve disruption by tissue crushing or blockade with tetrodotoxin. The response was inhibited by atropine and hexamethonium, indicating that a cholinergic component is part of the pathway. A small adrenergic component may also be present.
44. 44. GTP Saccone JR Harvey RA Baker 1994 Intramural neural pathways between the duodenum and sphincter of Oddi in the Australian brush-tailed possum in vivo J Physiol (Lond) 481 447 456 1:CAS:528:DyaK2MXisFymsb0%3D Saccone GTP, Harvey JR, Baker RA, et al.: Intramural neural pathways between the duodenum and sphincter of Oddi in the Australian brush-tailed possum in vivo. J Physiol (Lond) 1994, 481:447–456.
45. 45. Konomi H, Simula ME, Toouli J, et al.: Enhanced duodenal motility activates the sphincter of Oddi (SO)-duodenal reflex in the Australian possum in vitro. Proc World Congr IHPBA 2000, in press.