RESUMO
The effect of H2S on changes in erythrocyte volume was studied by spectrophotometrical and potentiometric methods. It was found that H2S donor NaHS (2.5, 10, and 100 µM) induced an increase in erythrocyte volume in heterosmotic media. Activation of Gardos channels with A23187 or ascorbate-phenazine methosulfate system causes erythrocyte shrinkage and hyperpolarization of their membrane, while addition of NaHS restored erythrocyte volume. The decrease in erythrocyte volume upon blockade of Na+,K+,2Cl- cotransporter (bumetanide) or anion exchanger (SITS) was abolished by H2S donor NaHS, which attested to an important role of these transporters and chlorine conductivity of the membrane in the maintenance of the homeostasis of blood cells.
Assuntos
Bumetanida/farmacologia , Membrana Eritrocítica/efeitos dos fármacos , Membrana Eritrocítica/metabolismo , Eritrócitos/efeitos dos fármacos , Eritrócitos/metabolismo , Sulfeto de Hidrogênio/farmacologia , Simportadores de Cloreto de Sódio-Potássio/metabolismo , Adulto , Feminino , Humanos , Canais de Potássio Ativados por Cálcio de Condutância Intermediária , Masculino , Adulto JovemRESUMO
Haifa Bay (HB), located along the northern Mediterranean shore of Israel was polluted with Hg from a chlor-alkali plant (ECI) and from the Qishon River industries, for decades. From the mid-1980s industrial Hg loads into HB decreased dramatically until their complete cessation in 2000. Consequently, concentrations in marine biota and sediments decreased almost to reference levels. However, during 2006-2014, an unexpected increase of total Hg (THg) concentrations was observed in three commercial fish species collected at northern HB (N.HB). To determine the cause of this increase, THg and methyl Hg (MeHg) were measured in seawater, coastal groundwater, suspended particulate matter, plankton, macroalgae, benthic fauna, and in marine and beach sediments. THg in groundwater and sediments from the vicinity of ECI were extremely high (up to 251 µg L-1 and 2200 ng g-1, respectively). MeHg concentrations in groundwater were low and constituted <0.1% of THg, except in the surf zone opposite the ECI, where MeHg constituted 0.2% of the THg. THg and MeHg concentrations were consistently higher in benthic biota and plankton from N.HB and northwards, compared to corresponding samples from southern HB (S.HB) and the reference site (RS). MeHg in bivalves and sponges from N.HB and SZ was higher than from S.HB and RS, despite having similar THg concentrations, which suggests a stronger source of MeHg in N.HB. Our findings suggest that the discharge into N.HB of Hg polluted groundwater under the ECI increased during the period 2006-2014. The Hg was assimilated by plankton or adsorbed onto inorganic particles, which were further ingested by benthic and pelagic consumers, as well as transported northward with the alongshore current. These findings demonstrate for the first time the potential of relic pollution in groundwater to increase heavy metal burdens in local marine food webs.
Assuntos
Cadeia Alimentar , Água Subterrânea , Animais , Baías , Monitoramento Ambiental , Israel , Mercúrio , Compostos de Metilmercúrio , Poluentes Químicos da ÁguaRESUMO
Injection of RS 102221 (selective antagonist of serotonin 5-HT2C receptors) in a dose of 2 mg/kg reduced anxiety of mice in the light-darkness test and decreased the amplitude of the startle reflex. RS 102221 in a dose of 1 mg/kg reduced prestimulus inhibition of the startle reflex. No behavioral changes in Porsolt test and motor activity in the open field test were detected. Hence, RS 102221 is characterized by selective anxiolytic activity, and 5-HT2C receptors are involved in the mechanisms of anxiety and startle reflex formation.