[The significance of zinc for contractility of smooth muscles and ultrastructure of their microfilaments in case of hypodynamic stress].
The aim of the study was to investigate the significance of zinc (added to food of the rabbits) for contractility of smooth muscles (effected by acetylcholine) and ultrastructure of their microfilaments in case of hypodynamic stress. Hypodynamic stress of 48-day duration was provoked for Chinchilla rabbits (n=20) by placing them in metal hutches. Every day (48 days) 10 rabbits, which had intervention received doses of zinc 0.3 mg/kg body wt (in form of zinc acetate). The rabbits (n=10) of the control group, which had no intervention were kept in vivarium conditions. The relaxation of smooth muscles from thoracic aorta as mediated by acetylcholine at a concentration from 10(-8) mol/l to 10(-4) mol/l was detected by means of a 6MXIC mechanotron in isometric regime. Response was expressed as the percentage of relaxation to prostaglandin F(2alpha) (10(-5) mol/l)-induced precontraction. The ultrastructure of the microfilaments of smooth muscles was evaluated by electron microscopy "Philips-300". In rabbits that received no zinc the relaxation of smooth muscles under the influence of acetylcholine was significantly lower than in rabbits that received zinc and lower in control rabbits. Also in rabbits without zinc supplement the investigation of ultrastructure of microfilaments revealed their damage (such change as irregular formation, drop out in flakes, microfilaments becoming shorter and thicker). In rabbits receiving zinc ultrastructure of microfilaments did not change.
Kusleikaite
Marija
M
Institute of Cardiology, Kaunas University of Medicine, Sukileliu 17, 3007 Kaunas, Lithuania. m.kusleikaite@delfi.lt
Stonkus
Sigitas
S
Laukeviciene
Ale
A
Kusleika
Gintaras
G
D000109:Acetylcholine / Q000494:pharmacology; D008841:Actin Cytoskeleton / Q000187:drug effects / Q000648:ultrastructure*; D000818:Animals; D007103:Immobilization; D008854:Microscopy, Electron; D009119:Muscle Contraction / Q000187:drug effects*; D009131:Muscle, Smooth, Vascular / Q000187:drug effects*; D011817:Rabbits; D013312:Stress, Physiological; D013997:Time Factors; D015032:Zinc / Q000494:pharmacology*
D015032:Zinc; D000109:Acetylcholine