Physiological and biochemical effects of acute exposure of fish to hydrogen sulfide.
ABSTRACT 1. Exposure of channel catfish to 0.5 mg/l H2S at 20 degrees C resulted in hyperpnea, followed by apnea, and finally respiratory arrest. 2. Catfish brain cytochrome oxidase activity was inhibited in vitro 18% by 10(-7) M H2S, 64% by 10(-6) M H2S, and 100% by 10(-4) M H2S. 3. When channel catfish were exposed to 0.1 mg/l H2S at 20 degrees C for 30 min, the cytochrome oxidase activity of the brain was inhibited 40% and that of the gill was inhibited 74%, while blood lactate rose from 11.6 to 38.1 mg/100 ml. 4. Catfish with nitrite-induced methemoglobinemia showed less inhibition of brain and gill cytochrome oxidase when exposed to hydrogen sulfide than did control fish. 5. Sulfide-inhibited brain cytochrome oxidase recovered from a 50% inhibition to control levels in channel catfish after 6 hr in freshwater at 10 degrees C. 6. Management practices are recommended which may help the commercial fish farmer alleviate the problem of the toxicity of sulfide to fish during harvest operations.
Article: Toxicology of hydrogen sulfide.[show abstract] [hide abstract]
ABSTRACT: Significant progress has been made in determining the action of sulfide on the primary target organs. It is reasonably clear that sulfide causes both K(+)-channel-mediated hyperpolarization of neurons and potentiation of other inhibitory mechanisms. It is not clear whether these processes are similar to those that occur in anoxia. Changes in perinatal and adult brain neurotransmitter content and release may be related to clinical impairment of cognition. H2S exposures at concentrations below the current occupational limits cause physiological changes in pulmonary function, thus suggesting that asthmatics are at risk. Studies of fetal and neonatal brain tissue have shown an abnormal development, and the long-term consequences of these neuronal changes have not yet been assessed. Finally, new approaches to therapy are required, such as the use of agents that actively remove sulfide from its sites of action. This may prove more useful in preventing some of the long-term adverse sequelae than the use of nitrites and hyperbaric O2, although the latter should be used in cases of pulmonary edema.Annual Review of Pharmacology 02/1992; 32:109-34. · 21.64 Impact Factor