Abstract
Background
Gastric electrical stimulation (GES) has been introduced for treating obesity. However, possible central mechanisms remain to be revealed. Hippocampus has been shown to be involved in the regulation of gastrointestinal functions. Changes in hypothalamic neuronal nitric oxide synthase (nNOS) have been observed in genetically obese rodents. The aim of this study was to investigate the involvement of nNOS with GES in the rodent hippocampus.
Methods
The effect of GES on gastric distension (GD) neurons was investigated using four different sets of parameters (GES-A, pulse train of standard parameters; GES-B, reduced on time; GES-C, increased pulse width, and GES-D: reduced pulse frequency), and the expression of nNOS in hippocampus was observed by fluoimmunohistochemistry staining.
Results
CA1 region neurons (90.8%) responded to GD, 50.6% of which showed excitation (GD-E neurons) and 49.4% showed inhibition (GD-I neurons). Most of GD-responsive neurons (63.3%) were excited with GES. The response to GES was associated with stimulation strength, pulse width and frequency. GD-E neurons (62.5%, 76.9%, 100%, and 62.3%) and GD-I (63.6%, 47.1%, 85.7% and 50.0%) showed excitatory responses to GES-A, GES-B, GES-C, and GES-D, respectively (P < 0.05, GES-C vs. others). nNOS immunoreactive (nNOS-IR) positive neurons were observed in hippocampus CA1, CA2-3 regions and the dentate gyrus. The expression of nNOS-IR positive neurons was significantly decreased in CA1 and CA2-3 region (P < 0.05) after GES (para-C) for 2 h.
Conclusions
Excitation of GD-responsive neurons and reduced expression of nNOS in the hippocampus are indicative of the central effect of GES.
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References
Flegal K, Carroll M, Kuczmarski R, et al. Overweight and obesity in the United States: prevalence and trends, 1960–1994. Int J Obes Relat Metab Disord. 1998;22:38–47.
Eckel R, Krauss R. American Heart Association call to action: obesity as a major risk factor for coronary heart disease. Circulation. 1998;97:2099–100.
Goldstein D. Beneficial health effects of modest weight loss. Int J Obes Relat Metab Disord. 1992;16:397–415.
Cigaina V. Gastric pacing as therapy for morbid obesity: preliminary results. Obes Surg. 2002;12:12S–6S.
D’argent J. Gastric electrical stimulation as therapy of morbid obesity: preliminary results from the French study. Obes Surg. 2002;12:21S–5S.
Zou LB, Yamada K, Sasa M, et al. Two phases of behavioral plasticity in rats following unilateral excitotoxic lesion of the hippocampus. Neuroscience. 1999;92:819–26.
Inglis FM, Day JC, Fibiger HC. Enhanced acetylcholine release in hippocampus and cortex during the anticipation and consumption of a palatable meal. Neuroscience. 1994;62:1049–56.
Healy S, Krebs J. Food storing and the hippocampus in Paridae. Brain Behav Evol. 1996;47:195–9.
Guan Y, Tang M, Jiang Z, et al. Excitatory effects of motilin in the hippocampus on gastric motility in rats. Brain Res. 2003;984:33–41.
Xu L, Sun X, Depoortere I, et al. Effect of motilin on the discharge of rat hippocampal neurons responding to gastric distension and its potential mechanism. Peptides. 2008;29:585–92.
Xu L, Sun X, Lu J, et al. Effects of gastric electric stimulation on gastric distention responsive neurons and expressions of CCK in rodent hippocampus. Obesity. 2008;16:951–7.
Isaacson RL. A fuzzy limbic system. Behav Brain Res. 1992;52:129–31.
Seifert W. Neurobiology of the hippocampus. New York: Academic Press; 1983.
Palmer R, Moncada S. A novel citrulline-forming enzyme implicated in the formation of nitric oxide by vascular endothelial cells. Biochem Biophys Res Commun. 1989;158:348–52.
Xiong KR, Ma TJ, Guo PS, et al. The projections of nitric oxide synthase (NOS) positive neurons to hippocampus from brainstem and hypothalamus in rat. J Si Chuan Anatomy. 1998;6:69–71.
Liu P, Smith PF, Appleton I, et al. Regional variations and age-related changes in nitric oxide synthase and arginase in the sub-regions of the hippocampus. Neuroscience. 2003;119:679–87.
Yamada K, Emson P, Hokfelt T. Immunohistochemical mapping of nitric oxide synthase in the rat hypothalamus and colocalization with neuropeptides. J Chem Neuroanatomy. 1996;10:295–316.
Sadler CJ, Wilding JP. Reduced ventromedial hypothalamic neuronal nitric oxide synthase and increased sensitivity to NOS inhibition in dietary obese rats: further evidence of a role for nitric oxide in the regulation of energy balance. Brain Res. 2004;1016:222–8.
Wang GJ, Yang J, Volkow ND, et al. Gastric stimulation in obese subjects activates the hippocampus and other regions involved in brain reward circuitry. Proc Natl Acad Sci U S A. 2006;103:15641–5.
Paxions G, Watson C. Rat brain in stereotaxic coordinate. London: Academic; 1998.
Tang M, Zhang J, Chen JDZ. Central mechanism of gastric electrical stimulation involving neurons in paraventricular nucleus of hypothalamus in rats. Obes Surg. 2006;16:344–52.
Isaacson RL. The Limbic System. New York: Plenum; 1982.
Davidson TL, Kanoski SE, Walls EK, et al. Memory inhibition and energy regulation. Physiol Behav. 2005;86:731–46.
Clifton PG, Vickers SP, Somerville EM. Little and often: ingestive behavior patterns following hippocampal lesions in rats. Behav Neurosci. 1998;112:502–11.
Hamm RJ, Pike BR, Phillips LL, et al. Impaired gustatory neophobia following traumatic brain injury in rats. J Neurotraum. 1995;12:307–14.
Jeanningros R. Modulation of lateral hypothalamic single unit activity by gastric and intestinal distension. J Auton Nerv Syst. 1984;11:1–11.
Zhang X, Renehan WE, Fogel R. Neurons in the vagal complex of the rat respond to mechanical and chemical stimulation of the gastrointestinal tract. Am J Physiol. 1998;274:331–41.
Ueta Y, Kannan H, Yamashita H. Inhibition of vasopressin secreting neurons of the paraventricular nucleus by gastric distension in rats. J UOEH. 1986;8:429–35.
Renaud LP, Tang M, McCann MJ. Cholecystokinin decreases and gastric distension activates oxytocinergic cells in rat hypothalamus. Am J Physiol. 1989;253:661–5.
Suemori K, Kobashi M, Adachi A. Effects of gastric distension and electrical stimulation of dorsomedial medulla on neurons in parabrachial nucleus of rats. J Auton Nerv Syst. 1994;48:1–229.
Ouyang H, Xing J, Chen JD. Tachygastria induced by gastric electrical stimulation is mediated via alpha- and beta-adrenergic pathway and inhibits antral motility in dogs. Neurogastroenterol Motil. 2005;17:846–53.
Xu X, Zhu H, Chen JD. Pyloric electrical stimulation reduces food intake by inhibiting gastric motility in dogs. Gastroenterology. 2005;128:43–50.
Yao S, Ke M, Wang Z, et al. Retrograde gastric pacing reduces food intake and delays gastric emptying in humans: a potential therapy for obesity? Dig Dis Sci. 2005;50:1569–75.
Zhu HB, Chen JDZ. Implantable gastric stimulation inhibits gastric motility via sympathetic pathway in dogs. Obes Surg. 2005;15:95–100.
Lin ZY, McCallum RW, Schirmer BD, et al. Effects of pacing parameters on entrainment of gastric slow waves in patients with gastroparesis. Am J Physiol. 1998;274:G186–91.
Familoni B, Abell T, Nemoto D, et al. Efficacy of electrical stimulation at frequencies higher than basal rate in canine stomach. Dig Dis Sci. 1997;42:892–7.
McCallum RW, Chen JD, Lin Z, et al. Gastric pacing improves emptying and symptoms in patients with gastroparesis. Gastroenterology. 1998;114:456–61.
Lin Z, Sarosiek FI, McCallum RW. Effects of high-frequency gastric electrical stimulation on gastric myoelectric acitivity in gastroparetic patients. Neurogastroenterol Motil. 2004;16:205–12.
Chen JDZ, Qian L, Quyang H, et al. Enteric neuromuscular disorders and pain group. Gastric electrical stimulation with short pulses reduces vomiting but not dysrhythmias in dogs. Gastroenterol. 2003;124:401–9.
Chen J, Ke M, Lin X, et al. Cisapride provides symptomatic relief in functional dyspepsia associated with gastric myoelectrical abnormality. Aliment Pharmacol Ther. 2000;14:1041–7.
Chang HK, Jang MH, Lim BV, et al. Administration of Ginseng radix decreases nitric oxide synthase expression in the hippocampus of streptozotocin-induced diabetic rats. Am J Chin Med. 2004;32:497–507.
Acknowledgements
This study was supported by grants from the Oklahoma Center for the Advancement of Science and Technology (HR 02-034R, Dr. J.Z. Chen); The National Natural Science Foundation of China (No. 30470642 and 30670780, Dr. L. Xu) and Qingdao Science and Technique Bureau (05-1-JC-93, Dr. L. Xu).
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L. Xu and X. Sun contributed equally to this work.
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Xu, L., Sun, X., Tang, M. et al. Involvement of the Hippocampus and Neuronal Nitric Oxide Synapse in the Gastric Electrical Stimulation Therapy for Obesity. OBES SURG 19, 475–483 (2009). https://doi.org/10.1007/s11695-008-9579-7
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DOI: https://doi.org/10.1007/s11695-008-9579-7