Interaction of NO and VIP in gastrointestinal smooth muscle relaxation.

Gastrointestinal (GI) smooth muscle cell activity is controlled by contractile cholinergic neurons and relaxant non-adrenergic non-cholinergic (NANC) neurons in the myenteric plexus between the circular and longitudinal muscle layer. Decreased or increased NANC relaxation might be involved in the pathophysiology of functional GI motility disorders. Vasoactive intestinal polypeptide (VIP) and nitric oxide (NO) are the primary inhibitory NANC neurotransmitters.

Nitrergic relaxation in rat gastric fundus: influence of mechanism of induced tone and possible role of sarcoplasmic/endoplasmic reticulum Ca2+ ATPase.

The aim of this study was to investigate the influence of the mechanism of induced tone and the role of sarcoplasmic/endoplasmic reticulum Ca2+ ATPase (SERCA) in nitrergic relaxation of rat gastric fundus. Prostaglandin F(2alpha) (PGF(2alpha)), thapsigargin (TSG) and cyclopiazonic acid (CPA) were used in concentrations that induced a similar contraction (20 g force/g tissue). Nifedipine (3 x 10(-7) M) completely relaxed PGF(2alpha)-contracted tissues and relaxed tissues contracted by TSG and CPA by 20 +/- 6% and 56 +/- 12% respectively; contraction induced by the three contractile agents was fully reversed by a general Ca2+ entry blocker 1-[2-(4-methoxyphenyl)-2-[3-(4-metoxyphenyl)propoxy]ethyl-1H-imidazole HCl (SKF 96365; 10(-5) M).

Further characterisation of particulate neuronal nitric oxide synthase in rat small intestine.

Neuronal NO-synthase (nNOS) was investigated in rat longitudinal muscle/myenteric plexus (LM/MP) tissue at the cellular and subcellular level. Using preparations and double immune staining and light and electron microscopy, we concluded that, in these preparations, nNOS is only present in neuronal cells. However, in spite of numerous attempts to morphologically identify the NOS-containing subcellular structure, no firm conclusions were possible.

L-citrulline recycling by argininosuccinate synthetase and lyase in rat gastric fundus.

The aim of this study was to investigate in rat gastric fundus whether L-citrulline, the co-product in the nitric oxide (NO) biosynthesis catalyzed by neuronal nitric oxide synthase (nNOS), can be converted back to the nNOS substrate L-arginine. Immunohistochemistry showed that argininosuccinate synthetase and argininosuccinate lyase, that mediate transformation of L-citrulline to L-arginine in the ureum cycle in hepatocytes, co-localize with nNOS. In longitudinal smooth muscle strips, L-arginine as well as L-citrulline (10(-3) M) was capable of completely respectively partially preventing the N(G)-nitro-L-arginine methyl ester (L-NAME) (3 x 10(-5) M)-induced inhibition of electrically induced nitrergic relaxations, whereas D-citrulline (10(-3) M) was not.

A randomized study of the efficacy and recovery of remifentanil-based and alfentanil anaesthesia with desflurane or sevoflurane for gynecological surgery.

We performed a prospective, randomized study comparing the efficacy and safety of the combination of remifentanil and the newer volatile anaesthetics desflurane and sevoflurane with a conventional anaesthetic technique using alfentanil and desflurane. Forty five ASA class I or II female patients were randomly assigned to one of three groups. Following induction with propofol patients received a continuous infusion of remifentanil in combination with either 0.