Jejunal and ileal absorptive function after a model of canine jejunoileal autotransplantation

Sarr, Michael G.; Duenes, Judith A.; Walters, A. M.

doi:10.1016/0022-4804(91)90100-z

Cited by 46 publications

(28 citation statements)

References 29 publications

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“…We evaluated responses to exogenously applied neuropeptides and to EFS to explore indirectly any changes of receptor expression, signaling pathways, or endogenous release of VIP and substance P by EFS which might contribute to enteric motor dysfunction after SBT. 1,[4][5][6] Exogenous VIP evoked a dose-dependent, profound inhibition of contractile activity, which was not affected by SBT and was not blocked by either the VIP antagonist, inhibition of NO production, or the combination of both. In contrast, the procontractile effect of exogenous substance P was diminished in animals 1 year after SBT and was blocked efficiently by the substance P antagonist in both groups.…”

Section: Discussionmentioning

confidence: 90%

Long-Term Effects of Extrinsic Denervation on VIP and Substance P Innervation in Circular Muscle of Rat Jejunum

Kasparek

Fatima

Iqbal

et al. 2007

Journal of Gastrointestinal Surgery

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Intestinal denervation contributes to enteric motor dysfunction after small bowel transplantation (SBT). Our aim was to determine long-term effects of extrinsic denervation on function of nonadrenergic, noncholinergic innervation with substance P and vasoactive intestinal polypeptide (VIP). Contractile activity of jejunal circular muscle strips from six age-matched, naive control rats (NC) and eight rats 1 year after syngeneic SBT was studied in tissue chambers. Spontaneous contractile activity did not differ between groups. Exogenous VIP inhibited contractile activity dose-dependently to a comparable degree in both groups. The VIP antagonist ([D-p-Cl-Phe(6),Leu(17)]-VIP) and the nitric oxide synthase inhibitor L-NG-nitro-arginine did not affect VIP-induced inhibition but increased contractile activity during electrical field stimulation (EFS) in both groups. Exogenous substance P increased contractile activity dose-dependently, greater in NC than SBT. The substance P antagonist ([D-Pro(2),D-Trp(7,9)]-substance P) inhibited effects of exogenous substance P and decreased the excitatory EFS response. Immunohistofluorescence showed tyrosine hydroxylase staining after SBT indicating sympathetic reinnervation. In jejunal circular muscle after chronic denervation, response to exogenous substance P, but not VIP, is decreased, whereas endogenous release of both neurotransmitters is preserved. Alterations in balance of excitatory and inhibitory pathways occur despite extrinsic reinnervation and might contribute to enteric motor dysfunction after SBT.

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Section: Discussionmentioning

confidence: 90%

Long-Term Effects of Extrinsic Denervation on VIP and Substance P Innervation in Circular Muscle of Rat Jejunum

Kasparek

Fatima

Iqbal

et al. 2007

Journal of Gastrointestinal Surgery

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“…Our hypothesis was that the obligate extrinsic denervation mandated by SBT leads to changes in the enteric neurotransmission mediated by these specific neurotransmitters. By using different models of denervation and evaluating the response to both exogenously applied neuropeptides and EFS, our goal was to explore indirectly any alterations in receptor expression or downstream mechanisms as well as changes in endogenous release of these neurotransmitters (by EFS), which might contribute to the enteric dysfunction after SBT [1,[3][4][5]. We showed that abdominal operations caused a previously unrecognized, reversible increase in VIP sensitivity 1 wk postoperatively, but neither disruption of enteric myoneuronal continuity (by intestinal transection) nor SBT altered VIP sensitivity after 8 wk.…”

Section: Discussionmentioning

confidence: 99%

“…Although outcomes after SBT have improved markedly over the last decade, due mainly to technical improvements and use of new immunosuppressants [1], many challenges in the postoperative management of these patients remain, one of which is enteric dysfunction with high stomal output or diarrhea [1,3,4]. Because diarrhea occurs in dog models of autotransplantation of the small bowel in which no immunosuppressants are used and immune phenomena are avoided, other factors such as the obligate extrinsic denervation by SBT are believed to contribute to the development of enteric dysfunction after SBT [5].…”

Section: Introductionmentioning

confidence: 99%

Role of VIP and Substance P in NANC Innervation in the Longitudinal Smooth Muscle of the Rat Jejunum—Influence of Extrinsic Denervation

Kasparek¹,

Fatima²,

Iqbal³

et al. 2007

Journal of Surgical Research

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“…55 Experimental evidence also indicates that the chronic extrinsic denervation of the small intestine does not affect net intestinal absorption of water and electrolytes. [55][56][57][58][59][60][61][62][63][64][65][66][67] We have also shown that CGx does not affect Na ϩ intake in rats fed 2% NaCl. 68 The exact hemodynamic mechanism by which CGx affects Ang II salt hypertension is still not completely clear and needs to be investigated further by chronic instrumentation of rats for measurements of cardiac output and total peripheral resistance determination.…”

Section: Discussionmentioning

confidence: 99%

Splanchnic Circulation Is a Critical Neural Target in Angiotensin II Salt Hypertension in Rats

2007

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Abstract-Chronic angiotensin II (Ang II) infusion, in rats fed high salt, engages the sympathetic nervous system to increase venomotor tone. The splanchnic sympathetic nervous system is the most important regulator of venous tone, indicating that splanchnic sympathetic nervous system activity may be increased in Ang II salt hypertension. We hypothesized that celiac ganglionectomy (CGx), to selectively disrupt sympathetic innervation to the splanchnic circulation, would attenuate arterial pressure (AP), and venous tone increases in Ang II salt hypertension. Rats fed 2% or 0.4% NaCl were instrumented to allow AP measurement by radiotelemetry at the same time as surgical CGx or sham operation. Ang II was delivered by minipump (150 ng/kg per minute) for 14 days. CGx reduced AP independent of salt diet during control. CGx markedly attenuated Ang II hypertension in rats on 2% NaCl but had little effect in rats fed 0.4% NaCl. To test the possibility that CGx exerted its effects via renal denervation, rats were subjected to the same protocol but received selective bilateral renal denervation. Renal denervation decreased AP during control but had no protective effect on Ang II hypertension and actually tended to exacerbate the pressor response. Finally, separate groups of rats underwent CGx or sham operation and were instrumented to allow repeated measures of mean circulatory filling pressure, an index of venous tone. In addition to attenuating Ang II salt hypertension, CGx completely prevented Ang II salt-induced increases in mean circulatory filling pressure and substantially attenuated depressor responses to acute ganglion blockade. We conclude that, in the presence of high salt, Ang II activates the splanchnic sympathetic nervous system to increase venomotor tone and AP. Key Words: angiotensin II Ⅲ sympathetic nervous system Ⅲ splanchnic circulation Ⅲ venomotor tone Ⅲ renal denervation W e have shown recently, using repeated measures of mean circulatory filling pressure (MCFP) in conscious undisturbed rats, that chronic infusion of angiotensin II (Ang II), only when administered in combination with a high-salt diet, activates the sympathetic nervous system (SNS) to increase venomotor tone. 1 This increase in venomotor tone may contribute to the pathogenesis of Ang II salt hypertension by increasing central blood volume, resulting in a translocation of blood from the highly compliant venous system to the less compliant arterial circulation. 1 This redistribution of blood volume and the well-documented impairment of renal excretory function caused by Ang II 2 would be major factors in increasing arterial pressure (AP) in this model. [3][4][5] Splanchnic veins and venules account for most of the active capacitance responses in the circulation and are richly innervated by the SNS. 6 -8 In fact, it has been estimated that innervation to the nonhepatic splanchnic organs accounts for half of the total norepinephrine (NE) released in the entire body. 9 Therefore, our recent observations in Ang II salt hypertension of neurog...

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Jejunal and ileal absorptive function after a model of canine jejunoileal autotransplantation

Cited by 46 publications

References 29 publications

Long-Term Effects of Extrinsic Denervation on VIP and Substance P Innervation in Circular Muscle of Rat Jejunum

Long-Term Effects of Extrinsic Denervation on VIP and Substance P Innervation in Circular Muscle of Rat Jejunum

Role of VIP and Substance P in NANC Innervation in the Longitudinal Smooth Muscle of the Rat Jejunum—Influence of Extrinsic Denervation

Splanchnic Circulation Is a Critical Neural Target in Angiotensin II Salt Hypertension in Rats

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