In Vitro Effects of Fentanyl on Aortic Viscoelasticity in a Rat Model of Melatonin Deficiency.

Melatonin influences arterial biomechanics, and its absence could cause remodeling of the arterial wall, leading to increased stiffness. Direct effects of fentanyl on the aortic wall have also been observed previously. This study aimed to evaluate in vitro the effects of fentanyl on aortic viscoelasticity in a rat model of melatonin deficiency and to test the hypothesis that melatonin deficiency leads to increased arterial wall stiffness.

Muscarinic modulation of nitrergic neurotransmission in guinea-pig gastric fundus.

Muscarinic receptor activation by (4-Hydroxy-2-butynyl)-1-trimethylammonium-m-chlorocarbanilate chloride (McN-A-343) was investigated both on NADPH-d staining and on electrically induced responses in guinea-pig gastric fundus. McN-A-343 (10 micromol L(-1)) significantly increased the optical density of NADPH-d positive neurones, while blockade of nitric oxide synthase with N(omega)-nitro-L-arginine (L-NA) decreased it, suggesting facilitation of nitric oxide (NO) production. Electrical field stimulation (EFS; 2 Hz, 0.

Non-synaptic release of [3H]noradrenaline in response to oxidative stress combined with mitochondrial dysfunction in rat hippocampal slices.

Brain ischemia is frequently associated with oxidative stress in the reperfusion period. It is known that noradrenaline (NA) is released in excess under energy deprivation by the sodium-dependent reversal of the monoamine carrier. However, it is not known how oxidative stress affects NA release in the brain alone or in combination with energy deprivation.

Participation of muscarinic acetylcholine receptors in nitric oxide pathway in cat duodenum.

The effect of activation of muscarinic acetylcholine subtype M1 receptors on the electrical field stimulation (EFS)-induced contractions in cat duodenal muscle strips was investigated. EFS elicited two types of responses: a) on-contraction; and b) off-contraction. The EFS-evoked responses were tetrodotoxin- and atropine-sensitive.

Participation of M1 receptors in NO pathway in cat ileum.

Electrical field stimulation (EFS) elicited two types of responses from longitudinal muscle strips of the distal cat ileum: contraction at switching on the stimulation (in 62% of the strips) and inhibition of the phasic contractions at switching on the stimulation followed by contraction in 38% of the strips. In all strips the muscarinic acetylcholine subtype M1-receptor agonist (4-Hydroxy-2-butynyl)-1-trimethylammonium-m-chlorocarbanilate chloride (McN-A-343) increased the tone and amplitude of the spontaneous contractions. On this background EFS elicited an inhibition of the phasic contractions at switching on the stimulation followed by contraction.