Nociceptin inhibits capsaicin-sensitive contraction to mesenteric nerve stimulation in the guinea-pig isolated ileum

Nerve-mast cell and smooth muscle-mast cell interaction mediated by cell adhesion molecule-1, CADM1

Mast cells are a native composer of connective tissue of the skin dermis and intestinal and respiratory mucosa. Independent lines of accumulated evidence indicate the existence of an intensive bidirectional crosstalk between mast cells and sensory nerves and suggest that mast cells and sensory nerves may be viewed as a functional unit, which could be of crucial importance in neuroimmunological pathways. Mast cells appear to have a property of influencing smooth muscle function via not only such nerve-mast cell effects, but also direct pathways. In bronchial asthma, mast cells infiltrate the airway smooth muscle layer, and interact directly with smooth muscle cells, suggesting pathogenic roles for mast cells in airway obstruction. Current studies on mast cell biology identified a novel adhesion molecule of mast cells, namely cell adhesion molecule-1, CADM1. This molecule is unique, because it serves as not only simple glue but also appears to promote functional communication between nerve and mast cells and between smooth muscle and mast cells.

ORL-1 receptor mediates the action of nociceptin on ascending myenteric reflex pathways in rats

BACKGROUND AND AIMS

Nociceptin is the endogenous agonist of the "orphan" opioid receptor-1 (ORL-1). We investigated whether activation of the ORL-1 receptor influences smooth muscle contractility and enteric neurotransmission within ascending myenteric reflex pathways of rats.

METHODS

Reverse transcriptase polymerase chain reaction was performed to evaluate the presence of ORL-1 receptors. The ascending part of the ascending myenteric reflex in rats was studied in ileal segments using a 3-chambered organ bath. Intracellular recordings were performed to evaluate pharmacologic effects on excitatory and inhibitory junction potentials (EJP; IJP). Single- and double-labeling immunohistochemistry was used to examine the distribution of ORL-1 within the intestinal wall.

RESULTS

ORL-1 expression and immunoreactivity was found in the large majority of myenteric neurons. In addition to the cholinergic myenteric neurons, all nitrergic myenteric neurons expressed the ORL-1 receptor. Nociceptin significantly reduced cholinergic twitch contractions, an effect that was reversed by the ORL-1 receptor antagonist [Nphe(1)]nociceptin(1-13)NH(2). Neither nociceptin nor [Nphe(1)]nociceptin(1-13)NH(2) had a direct influence on smooth muscle contractility. Nociceptin significantly reduced ascending myenteric reflex contractions and prolonged the latency from stimulation to contraction. Both effects were antagonized by [Nphe(1)]nociceptin(1-13)NH(2). Intracellular recordings demonstrated that nociceptin reduces the cholinergically mediated EJP and the nitrergic phase of IJP in a concentration-dependent manner, effects that were reversible in presence of [Nphe(1)]nociceptin(1-13)NH(2).

CONCLUSIONS

We conclude that activation of ORL-1 receptors on myenteric neurons reduce excitatory and inhibitory neurotransmission within the gastrointestinal tract. This is accompanied by a reduction of the small intestinal peristaltic reflex response. These effects might be used pharmacologically.

Involvement of the SgIGSF/Necl-2 adhesion molecule in degranulation of mesenteric mast cells

Spermatogenic immunoglobulin superfamily (SgIGSF) expressed on nerve and mast cells, binds homophilically between both in culture. In the steady-state mesentery of mice, the proportion of morphologically degranulating mast cells was approximately 20%, and it increased nearly two-fold when the mesenteric nerve root was stimulated electrically. In contrast, there was no significant increase detectable in the mesentery of MITF-mutants, from which bone marrow-derived cultured mast cells (BMMCs) lack SgIGSF. BMMCs from SgIGSF-knockout mice transplanted to the mesentery of mast cell-deficient W/W(v) mice did not degranulate in response to the mesenteric nerve stimulation, whereas transfection with SgIGSF cDNA restored those responses. SgIGSF appeared to promote communication between nerves and mast cells in the murine mesentery.

Urodynamic effects of intravesical nociceptin/orphanin FQ in neurogenic detrusor overactivity: a randomized, placebo-controlled, double-blind study

OBJECTIVES

To evaluate the acute urodynamic effects of the neuropeptide nociceptin/orphanin FQ (N/OFQ) in a selected group of patients with neurogenic detrusor overactivity incontinence in a randomized, placebo-controlled, double-blind study.

METHODS

The study involved 14 patients who presented with neurogenic detrusor overactivity due to spinal cord injury. They were randomized to receive intravesical infusion of 1 microM N/OFQ or the same dose of [desPhe(1)]N/OFQ (the placebo). The urodynamic parameters were the bladder capacity, volume threshold for the appearance of detrusor overactivity, and the maximal bladder pressure. The study was performed on a double-blind basis: neither the patients nor the doctors who performed the instillation could distinguish the solution containing N/OFQ from that containing [desPhe(1)]N/OFQ. Data are expressed as the mean +/- SD of seven determinations. Data were statistically analyzed using the Student t test for paired or unpaired data and P <0.05 was set as the criterion for a statistically significant difference.

RESULTS

The two groups were well balanced with respect to mean age, male/female ratio, etiology of spinal cord disease, and years from the lesion. Also, the baseline mean values of bladder capacity, volume threshold for the appearance of detrusor overactivity, and maximal bladder pressure were similar. The intravesical infusion of the solution containing 1 microM N/OFQ produced the following changes: bladder capacity and volume threshold for the appearance of detrusor overactivity significantly increased from 139 +/- 48 mL to 240 +/- 61 mL, and from 84 +/- 32 mL to 201 +/- 68 mL, respectively. Maximal bladder pressure decreased from 81 +/- 25 cm H(2)O to 66 +/- 12 cm H(2)O; however, this difference was not statistically significant. The intravesical infusion of the solution containing 1 microM [desPhe(1)]N/OFQ did not produce any statistically significant modification of the urodynamic parameters.

CONCLUSIONS

The results of this study confirm and extend previous results showing that N/OFQ, but not the placebo, elicits a robust acute inhibitory effect on the micturition reflex in patients with a neurogenic bladder. These findings apply nociceptin orphan peptide receptor agonists as potential novel drugs for the treatment of neurogenic urinary incontinence.

Endogenous opiates: 2000

This paper is the twenty-third installment of the annual review of research concerning the opiate system. It summarizes papers published during 2000 that studied the behavioral effects of the opiate peptides and antagonists, excluding the purely analgesic effects, although stress-induced analgesia is included. The specific topics covered this year include stress; tolerance and dependence; learning, memory, and reward; eating and drinking; alcohol and other drugs of abuse; sexual activity, pregnancy, and development; mental illness and mood; seizures and other neurological disorders; electrical-related activity; general activity and locomotion; gastrointestinal, renal, and hepatic function; cardiovascular responses; respiration and thermoregulation; and immunological responses.