Search results for "Muscle"
showing 10 items of 3397 documents
Characterization of prejunctional muscarinic autoreceptors in the guinea-pig trachea
1991
1. The effects of ten muscarinic antagonists on electrically evoked [3H]-acetylcholine release and muscle contraction were compared in an epithelium-free preparation of the guinea-pig trachea that had been preincubated with [3H]-choline. 2. The M3-selective antagonists UH-AH 37, 4-diphenyl-acetoxy-N-piperidine methobromide and para-fluorohexahydrosiladiphenidol were more potent in reducing the contractile response than in facilitating the evoked [3H]-acetylcholine release. Hexahydrosiladiphenidol did not discriminate between pre- and postjunctional effects. The rank order of the postjunctional potencies of the ten antagonists as well as the postjunctional pA2 values obtained for hexahydrosi…
Inhibitory and excitatory muscarinic receptors modulating the release of acetylcholine from the postganglionic parasympathetic neuron of the chicken …
1992
The effects of muscarinic receptor antagonists on ACh release were studied in the absence or presence of cholinesterase (ChE) inhibition using the isolated perfused chicken heart. Presynaptic inhibitory muscarinic autoreceptor were characterized by determining the potency of various antagonists to enhance [3H]-ACh release evoked by field stimulation (3 Hz, 1 min). The order of potencies was: (±)-telenzepine > atropine > 4-DAMP > silahexocyclium > pirenzepine > hexahydro-siladifenidol > AF-DX 116. The comparison with known pA2 values for M1-, M2- and M3-receptors revealed that the presynaptic autoreceptor meets the criteria of an M1-receptor. Basal, not electrically evoked overflow of unlabe…
Increase by NO synthase inhibitors of acetylcholine release from guinea-pig myenteric plexus
1994
The effects of nitric oxide (NO) synthase inhibitors on the electrically evoked release of [3H]acetylcholine were studied in guinea-pig myenteric plexus preparations preincubated with [3H]choline. NG-monomethyl-L-arginine (EC50 5.3 mumol l-1) and NG-nitro-L-arginine (EC50 1.3 mumol l-1) concentration-dependently increased the evoked release of [3H]acetylcholine without affecting the basal outflow. The facilitatory effect of NG-mono-methyl-L-arginine was prevented by L-arginine but not by D-arginine. The results suggest that endogenous NO inhibits the depolarisation-evoked release of acetylcholine.
Choline inhibits acetylcholine release via presynaptic muscarine receptors
1981
The effect of exogenous choline on the outflow of 3H-acetylcholine evoked by field stimulation was studied on the myenteric plexus-longitudinal muscle preparation of the guinea pig. Choline at concentrations of 100 microM and higher depressed the evoked outflow of 3H-acetylcholine in a concentration-dependent manner. The EC50 for the inhibitory action was 300 microM. Scopolamine (10 nM) antagonized the effect of choline which indicates that the inhibition of 3H-acetylcholine outflow is mediated by muscarine receptors. The findings imply that choline at high concentrations does not improve cholinergic synaptic neurotransmission in tissues that are endowed with presynaptic muscarine receptors…
Two types of neuronal muscarine receptors modulating acetylcholine release from guinea-pig myenteric plexus
1985
Longitudinal muscle strips of the guinea-pig ileum were incubated with [3H]choline and the effects of muscarinic agonists on smooth muscle contraction and on spontaneous and electrically-evoked outflow of tritium were studied. Muscarine and pilocarpine concentration-dependently increased both muscle contraction and spontaneous outflow of [3H]ACh, and inhibited the electrically-evoked outflow of [3H]ACh. The increase in spontaneous outflow was prevented by tetrodotoxin and scopolamine, but not by hexamethonium. Oxotremorine (1-100 microM) did not increase the spontaneous outflow of tritium. Pirenzepine in concentrations of 10 and 100 nM hardly affected the muscle contractions induced by pilo…
The effects of active vs. passive recovery on riding performance during a simulated motocross race
2021
Aims: Motocross consists of two races of 30 min with a break in between. Recovery between races is paramount to performance, this study aimed to compare the effects of active and passive recovery between motocross races on riding performance. Methods: Thirteen elite and non-elite racers performed two races of 30 min with 1 h break, twice with two-week interval. Between the races active (20 min ergometer cycling at 60% of HRmax) or passive recovery (no activity) were executed in a randomized order. Lap times, heart rate during riding, blood lactate, reaction time, handgrip strength, upper back pull strength, counter movement jump height, and medicine ball throw distance were measured before …
Effects of lindane on fish carbohydrate metabolism.
1991
Exposure of the European eel (Anguilla anguilla) to a high sublethal concentration of 0.335 ppm (0.50 of the 96-hr LC50) of lindane for 6, 12, 24, 48, 72, and 96 hr affected carbohydrate metabolism. Muscle glycogen levels decreased significantly (P less than 0.05) at 6, 12, 24, 48, 72, and 96 hr; liver glycogen content did not decline at any time. Muscle glucose levels in fish were elevated at 6, 12, 24, 48, 72, and 96 hr but in liver, the levels increased only at 96 hr. Mean values of muscle and liver pyruvate were elevated significantly (P less than 0.05) at 6, 12, 24, 48, and 72 hr. Muscle lactate levels increased at 6, 12, 24, and 48 hr in pesticide-treated fish. Liver lactate levels we…
Resistance Training with Blood Flow Restriction Compared to Traditional Resistance Training on Strength and Muscle Mass in Non-Active Older Adults: A…
2021
Low-intensity training with blood flow restriction (LI-BFR) has been suggested as an alternative to high-intensity resistance training for the improvement of strength and muscle mass, becoming advisable for individuals who cannot assume such a load. The systematic review aimed to determine the effectiveness of the LI-BFR compared to dynamic high-intensity resistance training on strength and muscle mass in non-active older adults. A systematic review was conducted according to the Cochrane Handbook and reportedly followed the PRISMA statement. MEDLINE, EMBASE, Web of Science Core Collection, and Scopus databases were searched between September and October 2020. Two reviewers independently se…
Add-On Effect of Postural Instructions to Abdominopelvic Exercise on Urinary Symptoms and Quality of Life in Climacteric Women with Stress Urinary In…
2021
The aim of this study was to investigate the add-on effect of postural instructions to an abdominopelvic exercise program on incontinence urinary symptoms (UI symptoms) and quality of life (QoL) in climacteric women with stress urinary incontinence (SUI). A randomized controlled trial was performed with a total of 40 climacteric women with SUI aged between 46 and 75 years old. Participants were randomly assigned to two groups: a group performing an abdominopelvic exercise program (AEP) (n = 20) and a group performing abdominopelvic exercise with the addition of postural instructions (AEPPI) (n = 20). Primary outcome measures were UI symptoms, UI impact and QoL related to UI (UI-QoL), measur…
Short and Long-Term Trainability in Older Adults: Training and Detraining Following Two Years of Multicomponent Cognitive—Physical Exercise Training
2020
Despite the benefits of multicomponent physical&ndash