Oesophageal epithelial innervation in health and reflux oesophagitis.

BACKGROUND: The response of the oesophagus to refluxed gastric contents is likely to depend on intact neural mechanisms in the oesophageal mucosa. The epithelial innervation has not been systematically evaluated in health or reflux disease. AIMS: To study oesophageal epithelial innervation in controls, and also inflamed and non-inflamed mucosa in patients with reflux oesophagitis and healed oesophagitis. PATIENTS: Ten controls, nine patients with reflux oesophagitis, and five patients with healed oesophagitis. METHODS: Oesophageal epithelial biopsy specimens were obtained at endoscopy. The distribution of the neuronal marker protein gene product 9.5 (PGP), and the neuropeptides calcitonin gene related peptide (CGRP), neuropeptide Y (NPY), substance P (SP), and vasoactive intestinal peptide (VIP) were investigated by immunohistochemistry. Density of innervation was assessed by the proportion of papillae in each oesophageal epithelial biopsy specimen containing immunoreactive fibres (found in the subepithelium and epithelial papillae, but not penetrating the epithelium). RESULTS: The proportion of papillae positive for PGP immunoreactive nerve fibres was significantly increased in inflamed tissue when compared with controls, and non-inflamed and healed tissue. There was also a significant increase in VIP immunoreactive fibres within epithelial papillae. Other neuropeptides showed no proportional changes in inflammation. CONCLUSIONS: Epithelial biopsy specimens can be used to assess innervation in the oesophagus. The innervation of the oesophageal mucosa is not altered in non-inflamed tissue of patients with oesophagitis but alters in response to inflammation, where there is a selective increase (about three- to fourfold) in VIP containing nerves.

Radiation-induced changes in neuropeptides in the rat urinary bladder.

PURPOSE: To determine whether there was a change in innervation in the rat urinary bladder following x-ray irradiation. MATERIALS AND METHODS: The urinary bladders were obtained from rats irradiated 6 months previously with single doses of 15 Gy and 25 Gy x-radiation, and from nonirradiated (control) animals. They were examined immunohistochemically to localize neuropeptide Y (NPY), substance P (SP), vasoactive intestinal polypeptide (VIP), calcitonin gene-related peptide (CGRP), met-enkephalin (m-ENK), leu-enkephalin (l-ENK), somatostatin (SOM) and the enzyme, tyrosine-hydroxylase (TH). Computer assisted image analysis was used to assess the density of immunoreactive nerve fibres. RESULTS: The greatest density of nerves observed in the bladder from control animals contained NPY, followed (in decreasing order) by CGRP, VIP, SP and TH. The nerves appeared to run predominantly along the longitudinal axis of the circular and longitudinal muscle fibres. SP-, CGRP-, TH- and occasionally VIP-immunoreactive nerves were observed in the lamina propria, at the base of the urothelium. Perivascular nerves containing neuropeptides and TH were observed throughout the bladder wall. There was an absence of m-ENK-, l-ENK- and SOM-immunoreactive nerves in the control and irradiated rat urinary bladders. In the rat urinary bladder irradiated with 25 Gy x-radiation, there was a significant increase (P < 0.05) in the density of NPY-, TH- and SP- but not CGRP- and VIP-immunoreactive nerves. There were regional differences within the bladder, that is, there was an increase in VIP-, CGRP- and SP-immunoreactive nerves around and within the urothelium. NPY-immunoreactive nerves were seen in the connective tissue and elastic fibres of the lamina propria for the first time. An increase in the density or fluorescence intensity of perivascular TH- but not neuropeptide-containing nerves was observed. CONCLUSIONS: The increase in the density of NPY-, SP- and TH-immunoreactive nerves in the irradiated bladders may be due to axonal sprouting which contributes to the symptoms of radiation injury.

An increase of neuropeptide Y but not nitric oxide synthase-immunoreactive nerves in the bladder neck from male patients with bladder neck dyssynergia.

PURPOSE: To determine the distribution of neuropeptides in male patients with bladder neck dyssynergia and benign prostatic hyperplasia. MATERIALS AND METHODS: Bladder neck tissue, obtained from male patients with bladder neck dyssynergia (BND) and control patients with benign prostatic hyperplasia (BPH), was studied immunohistochemically for protein gene product 9.5 (a general neuronal marker), vasoactive intestinal polypeptide, neuropeptide Y, calcitonin gene-related peptide, substance P, growth associated protein 43 and nitric oxide synthase. RESULTS: In the bladder neck from control patients, the greatest density of nerves contained protein gene product 9.5, followed in decreasing order by neuropeptide Y; vasoactive intestinal polypeptide; calcitonin gene-related peptide; nitric oxide synthase; substance P and serotonin. The neuropeptides were found in the smooth muscle and were also associated with blood vessels. In patients with BND there was a statistically significant increase (P < 0.05) in the density of protein gene product 9.5- and neuropeptide Y-immunoreactive nerves in the smooth muscle and the base of the mucosa but not in blood vessels in the bladder neck, while the density of the other neuropeptides studied, nitric oxide synthase and serotonin did not significantly change from that of control tissue. Growth associated protein 43-immunoreactive nerves were absent from the bladder neck from both groups of patients. CONCLUSION: It is suggested that the increase in density of protein gene product 9.5- and neuropeptide Y-immunoreactive nerves, part of the sympathetic contractile system of the bladder neck, may exacerbate bladder outlet obstruction and thus play a role in the pathogenesis of BND.

Chronic ethanol consumption affects cholinoceptor- and purinoceptor-mediated contractions of the isolated rat bladder.

Isolated bladder strips from 12-week ethanol-fed, pair-fed and control adult male rats were investigated. Contractile responses to carbachol (CCh; 0.1-300 microM) were statistically significantly potentiated in the ethanol-fed group compared to pair-fed and control. Contractions to beta,gamma-methylene ATP (beta,gamma-MeATP; 1-300 microM) were statistically significantly potentiated in the ethanol-fed group at the highest concentration tested (300 microM). Neurogenic contractions (0.5-32 pps) from the ethanol-fed group in the absence of atropine and after desensitisation by alpha,beta-methylene ATP (alpha,beta-MeATP; 3 microM), were significantly potentiated compared to the pair-fed and control groups; in the presence of atropine (1 microM), neurogenic contractions were significantly augmented at the higher frequencies. It is concluded that chronic ethanol treatment affects both cholinoceptor- and purinoceptor-mediated contractions of the rat bladder.

Contribution of ATP and nitric oxide to NANC inhibitory transmission in rat pyloric sphincter.

1. Changes in isometric tension were recorded from circular muscle strips of rat pyloric sphincter in vitro, in response to electrical field stimulation and exogenously applied muscle relaxants. 2. Concentration-response relationships were studied for relaxation to exogenously applied adenosine 5'-triphosphate (ATP) and two analogues, 2-methylthioATP (2-MeSATP) and alpha,beta-methylene ATP (alpha,beta-MeATP). These drugs evoked concentration-dependent relaxation of rat pyloric sphincter with an order of potency 2-MeSATP > ATP >> alpha,beta-MeATP, indicating the presence of P2y-purinoceptors. The IC50 value of each nucleotide was: 2-MeSATP, 5.0 x 10(-8); ATP, 7.9 x 10(-6) M; alpha,beta-MeATP showed only slight activity at a concentration of 0.1 mM. 3. Frequency-response relationships for relaxations evoked by electrical field stimulation (EFS) were studied in the absence and presence of 10 microM NG-nitro-L-arginine methyl ester (L-NAME, an inhibitor of nitric oxide (NO) synthesis) and 20 microM reactive blue 2 (a P2y-purinoceptor antagonist). It was found that these substances significantly reduced the relaxant response of rat pyloric sphincter to EFS by 40% and 50% respectively. In the presence of both L-NAME and reactive blue 2 the responses were reduced by 75%. 4. Concentration-response relationships were studied for ATP and 2-MeSATP in the presence of L-NAME. It was found that L-NAME did not significantly inhibit the relaxant responses to these drugs. 5. Concentration-response relationships for ATP and noradrenaline were studied in the presence of reactive blue 2 (20 microM); the P2y-antagonist significantly inhibited the relaxant response to ATP, but not that to noradrenaline. 6. The distribution of nitric oxide synthase in rat pyloric sphincter was investigated immunohistochemically,with immunoreactive nerve fibres found throughout the circular muscle layer and myenteric plexus of the sphincter.7. While abundant vasoactive intestinal polypeptide (VIP)-containing nerve fibres were demonstrated immunohistochemically in the pyloric sphincter, relaxations to VIP (1 nM-0.3 micro M) were not observed in this preparation.8. It is concluded that ATP, acting through P2y-purinoceptors, and NO contribute to NANC inhibitory neurotransmission in rat pyloric sphincter. NO appeared to contribute to the later component of NANCrelaxation. The action of ATP was not mediated by NO, and VIP did not contribute to the NANCinhibitory responses in this preparation.

Prevention of neuropathy in the pyloric sphincter of streptozotocin-diabetic rats by gangliosides.

BACKGROUND: The effect of diabetes on the density of peptide-containing nerves in the pyloric sphincter of streptozotocin-induced diabetic rats and the possible preventive action of the ganglioside mixture AGF1 on the diabetes-induced changes were investigated. METHODS: Immunohistochemical techniques were used to localize the general neuronal marker protein gene product 9.5 and the neuropeptides, calcitonin gene-related peptide, [met]-enkephalin, neuropeptide Y, substance P, and vasoactive intestinal polypeptide. RESULTS: The density of neurones showing immunoreactivity to the above peptides in nerves supplying the thickened circular muscle layer of the pyloric sphincter was reduced extensively in diabetic rats. In the ganglioside-treated diabetic animals, this reduction was prevented; indeed, calcitonin gene-related peptide- and substance P-like immunoreactivity in the ganglioside-treated diabetic rats exceeded that seen in control animals. In the ganglioside-treated controls, there was no significant difference in the peptide immunoreactivity from that of untreated controls. CONCLUSIONS: The results of the present study show that the ganglioside mixture AGF1 is effective in protecting the nerves of the pyloric sphincter from diabetes-induced changes.