Lead effects on non-adrenergic non-cholinergic relaxations in the rat gastric fundus.
The effect of lead exposure on non-adrenergic non-cholinergic (NANC) relaxations in rat gastric fundus was evaluated in this work. Wistar rats were divided into four groups: The control group received tap water and the three other received 0.008% of lead acetate in their drinking water for 15, 30 and 120 days. NANC relaxations induced by electrical field stimulation (0.5-8 Hz, 1 ms, 60 V) of gastric fundus strips was inhibited in all groups treated with lead. The strips from groups, control and 120 days of lead treatment (LEAD 120), were incubated with L-NOARG (100 microM). The presence of this blocker did not produce any additional inhibition. Sodium nitroprusside (10(-10)-10(-6) M) and 8-Br-GMPc (3 x 10(-8)-3 x 10(-4) M) produced dose-dependent relaxations in strips of both groups control and LEAD 120, however, in the LEAD 120, the potencies were significantly reduced from 7.32 +/- 0.05 to 6.40 +/- 0.09 (n = 5) and 4.26 +/- 0.06 to 3.69 +/- 0.05 (n = 5), respectively. Our data suggest that the chronic exposure to lead inhibits NANC relaxations probably by modulating NO release from NANC nerves and/or by interacting with intracellular transducer mechanisms in rat gastric fundus.
Santos
M R V
MR
Departamento de Fisiologia, Universidade Federal de Sergipe, Av Marechal Rondon SN, São Cristóvão-SE 49100-000, Brazil.
Marchioro
M
M
Antoniolli
A R
AR
D000818:Animals; D006152:Cyclic GMP / Q000031:analogs & derivatives / Q000494:pharmacology; D004558:Electric Stimulation; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005748:Gastric Fundus / Q000187:drug effects* / Q000502:physiology; D066298:In Vitro Techniques; D007854:Lead / Q000633:toxicity*; D008297:Male; D009126:Muscle Relaxation / Q000187:drug effects*; D020030:Nitric Oxide Donors / Q000494:pharmacology; D019001:Nitric Oxide Synthase / Q000037:antagonists & inhibitors; D019335:Nitroarginine / Q000494:pharmacology; D009599:Nitroprusside / Q000494:pharmacology; D051381:Rats; D017208:Rats, Wistar
D004791:Enzyme Inhibitors; D020030:Nitric Oxide Donors; D009599:Nitroprusside; D019335:Nitroarginine; D007854:Lead; C016276:8-bromocyclic GMP; D019001:Nitric Oxide Synthase; D006152:Cyclic GMP