Changes in the Contractile Activity and Reactivity to 5-HT of Smooth Muscles of Rats Following Total Body Irradiation with Accelerated Electrons.

Background: Besides its “classical” neurotransmitter function in the central and peripheral nervous systems, serotonin, or 5-hydroxytryptamine (5-HT) is also a local hormone in a number of tissues, including those of the GI tract. Radiation is known to be able to disrupt certain functions of the tract, modulated by 5-HT-signaling pathways, or the serotonin receptors themselves.

Aim: The present investigation focused on clarifying the nature and extent of influence of an accelerated electron beam with energy of 9 MeV on the serotonergic mediation of healthy smooth muscle gastric tissue of rats following total body irradiation of the animals.

Biochemical Changes in Experimental Rat Model of Abdominal Compartment Syndrome.

Background: Increased intra-abdominal pressure (IAP) causes tissue ischemia, subsequent hypoxia, and impairment of normal tissue metabolism. Elevation of IAP above 20 mmHg leads to progression of abdominal compartment syndrome (ACS) that is associated with organ dysfunction or failure not previously manifested.

Aim: To evaluate the eff ects of diff erent grades and time of exposure to IAP on biochemical parameters and oxidative stress in organs aff ected by ischemia using previously developed rat model.

New biological properties of coffee melanoidins.

Water-soluble melanoidins isolated from roasted coffee induced ex vivo changes in the bioelectric and contractile activity of rat circular gastric smooth muscle tissues. They provoked a depolarization of smooth muscle cellular membranes and an increase in Ca²⁺-influx as evidenced by the increase in the frequency and amplitude of Ca²⁺-generated spike potentials. In the presence of 1 × 10⁻⁶ mol L⁻¹ acetylcholine and 1 × 10⁻⁶ mol L⁻¹ arecoline the melanoidin-evoked contraction was significantly reduced.

Sensitizing effect of tacrine on M-cholinergic receptors in gastric smooth muscle of rats.

Aim: To find if tacrine exerts a sensitizing effect on the cholinergic receptors of gastric smooth muscles, and study some of the mechanisms inducing it and measure the relative intensity of tacrine's effects on contractile activity.

Material And Methods: Isometric recording of the mechanical activity of gastric smooth muscle preparations; determination of acetyl-cholinesterase activity in smooth-muscle tissue homogenates using Ellman's method.

Results: We found that the threshold concentration for tacrine not reducing the acetylcholinesterase activity and not having an effect on the smooth muscle preparations was 1 x 10(-8) mol/l.

Testing biological activity of model Maillard reaction products: studies on gastric smooth muscle tissues.

Water-soluble Maillard reaction products obtained from five different model systems were investigated for their effects upon the mechanical activity of rat gastric smooth muscle. Most of the total Maillard reaction products applied at concentration of 1.5 mg/ml evoked contractions; among them the product obtained from arginine and glucose (Arg-Glc) produced the most powerful contractions.