Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0011570 (depression)
 172,036 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

When plasma proteins are diluted with buffer the ionic strength and ionic composition of that buffer affects the interactions between thyroxine (T4) and its plasma protein-binding sites. Increases in phosphate, chloride or barbiturate ion concentration from 50 to 200 mmol/l caused a significant decrease in the affinity of plasma proteins for T4, and a concurrent increase in the concentration of unbound T4. These results cannot be completely accounted for by changes in ionic strength since at the same ionic strength different anions caused quantitatively different effects on unbound T4 concentration. The degree of depression of T4 binding by the three anions studied was in the order barbiturate greater than chloride greater than phosphate. The results of a systematic study on the composition of diluent buffer systems indicated that when a 50 mM-sodium phosphate-100 mM-NaCl buffer (pH 7-4) was used as a plasma diluent, there were unlikely to be gross changes in the T4-binding properties of plasma proteins with dilution.
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PMID:Effect of ionic strength and ionic composition of assay buffers on the interaction of thyroxine with plasma proteins. 0 Apr 47

The electrolyte changes and renal hemodynamic adjustment to hypertonic sodium bicarbonate (NaHCO3) correction of a metabolic acidosis were studied in 4 neonatal lambs and in 2 controls. PAH clearance increased from 0.92 to 1.65 ml/min/kg (p less than 0.05), urine flow from 0.37 to 0.61 ml/min/kg (p less than 0.05), and Na excretion from 8.4 to 23.7 muEq/min/kg (p less than 0.05) during the NaHCO3 infusion. These increases were transient and returned to pre-infusion levels following NaHCO3 infusion. Calculation of Na intake and output revealed a net retention of 5.1 mEq/kg in the study lambs which was reflected in a rise of serum Na and osmolarity (Osm) during the post-NaHCO3 -infusion period. The extraction ratio of sodium p-aminohippurate (EPAH) and its relationship to arterial pH were studied in 4 additional lambs. The EPAH did not change with metabolic acidosis but for unknown reasons, the infusion of NaHCO3 resulted in a temporary depression of EPAH (p less than 0.001).
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PMID:PAH clearance, sodium excretion, and PAH extraction ratio in acidotic near-term lambs treated with hypertonic sodium bicarbonate. 0 40

Renal reabsorption of bicarbonate was studied in Merino ewes during carbonic anhydrase inhibition. Bicarbonate reabsorption was directly proportional to plasma bicarbonate concentration. No tubular maximum for bicarbonate was demonstrated. Elevation of arterial PCO2 or depression of arterial pH caused slight increases in bicarbonate reabsorption. The data suggest that bicarbonate is reabsorbed by 2 distinct processes. The quantitatively more significant process may involve ionic reabsorption of bicarbonate secondary to Na+ reabsorption and a relatively minor part of bicarbonate reabsorption may be secondary to H+ secretion.
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PMID:The effect of carbonic anhydrase inhibition on bicarbonate reabsorption. 0 67

Microwave irradiation of 6 kw at 2450 MHz for 300 msec was sufficient to completely inactivate mouse brain cholinesterase and choline acetyltransferase. After this method of sacrifice, the acetylcholine contents of mouse brain regions, given in nanomoles per gram, were found to be: striatum, 81; medulla-pons, 44; diencephalon-midbrain, 34; hippocampus, 31; cerebral cortex, 26; and cerebellum, 17. Sodium pentobarbital caused a dose-dependent increase in whole brain acetylcholine. A maximal increase of 81% in whole brain was seen at 15 minutes with 80 mg/kg of sodium pentobarbital. The increase in acetylcholine after sodium pentobarbital treatment was not caused by anoxia from respiratory depression or by hypothermia. All brain regions except the cerebellum exhibited an increase in acetylcholine after pentobarbital treatment. Fifteen minutes after treatment, cerebellar acetylcholine was significantly decreased. However, at the time when half of the animals had regained the righting reflex, the unconscious mice showed an increase in cerebellar acetylcholine which was statistically significant as compared to control. The relative accumulation rate of acetylcholine calculated for cerebral cortex and hippocampus was higher than that for striatum although the absolute rate of accumulation of ACh was higher in the striatum. Thus, after sodium pentobarbital treatment, the cerebral cortex and hippocampus exhibit a greater cholinergic response than the striatum.
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PMID:Use of 300-msec microwave irradiation for enzyme inactivation: a study of effects of sodium pentobarbital on acetylcholine concentration in mouse brain regions. 0 94

The chorontropic response of isolated rabbit atria in normal Tyrode's medium increases monotonically with increasing doses of histamine (9 X 10-7 -9 X 10-4 M). Plots of the inverse of response against the inverse of concentration were linear; and from these plots were derived values fro the theoretical maximum response at 'infinite' dose and for pH histamine concentration required to evoke a half maximum response. Alteration of pH by changing (HCO3-) at a constant pCO2, (Na) and osolality did not appreciably affect the response to histamine in the range pH 7.0-7.6. However, at pH below 7.0 the magnitude of histamine response was reduced at all concentrations of histamine tested. In the pH range 7.0-7.6, additions of NaHCO3 at constant pCO2 increased the spontaneous rate of rabbit atria (in the absence of histamine); however, there was little effect of changing pH (in this range) by altering (HCO3-) at constant pCO2 when (Na+) and osmolaity were kept constant. Immersion in solutions at pH's less than 7.0 led to decline in spontaneous rate and force contraction. It is probable that depression of adenyl cyclase activity rather than a specific change in ionization of histamine receptor is responsible for a decreased response to histamine at pH 6.9.
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PMID:The effect of pH on rabbit atrial response to histamine. 0 37

The response of rainbow trout Na+ and Cl- uptake systems to acute acidosis was tested by slow infusion of lactic acid into anaesthetized animals. Depression of blood pH by 0-4 pH unit had no effect on influx rates for either ion, and we conclude that gill ion uptake systems do not respond rapidly to blood pH changes.
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PMID:Responses of trout gill ion transport systems to acute acidosis. 0 9

In the longitudinal muscle strip of guinea pig ileum phenoxybenzamine (POB) produces a maximum parallel shift of 0.7 log units in the dose-response curve to histamine. In the presence of sodium thiosulfate in the wash fluid the parallel shift whith retention of maximum response increases to about 2 log units, and a similar value is obtained for Nethyl-N-(2-bromoethyl)-1-naphthylamine. The The agent N-ethyl-N- (2-chloroethyl)benzylamine produces a significantly smaller shift of dose-response curve of 1.53 log units before the maximum response becomes depressed. The receptor-specific depression of maximum response produced by higher doses of POB is reversed by sodium thiosulfate and by bovine serum albumin, while the parallel shift in dose-response curve is unaffected by both treatments. These findings may be explained by a hypothesis involving interaction of 2-haloalkylamines at two sites.
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PMID:Blockade of histamine-induced contractions of guinea pig ielum by beta-haloalkylamines. 0 4

The effect of back diffusion of H+ PON THE POTENTIAL DIFFERence (PD), electrical resistance (R), and short circuit current (Isc) of spontaneously secreting and burimamide-inhibited amphibian gastric mucosae were studied in vitro. When back diffusion of H+ was induced by the passage of an electrical current of 510 mua per cm2 from the secretory (S) side of pH 2.25 to the nutrient side (N) for 30 min, the spontaneously secreting mucosae showed small decreases in PD (23.6 leads to 16.2 mv) and Isc (80 leads to 61 mua per cm2) but no significant change in R. In the burimamide-inhibited mucosae there were marked and significantly greater decreases of PD (26.8 leads to 3.4 mv), R (473 leads to 170 ohms cm2) and Isc (50 leads to 13 mua per cm2). When back diffusion of H+ was induced by establishing a concentration gradient of H+ from S leads to N or by exposing the secretory surface to sodium taurocholate with secretory pH 2.25, the burimamide-inhibited tissue demonstrated significantly greater depression of the electrical parameters than the secreting mucosae. Intracellular pH, measured by the 5,5-dimethoxyazolidine-2,4-dione method, was significantly higher in the histamine-stimulated tissues (7.28) than in the metiamide-inhibited tissues (7.11). These studies strongly suggest that the secretory status of the mucosa and hence its acid-base status are important determinants in the tolerance of the tissue to exogenous back diffusion of H+. The measure of absolute loss of H+ From the mucosal solution alone may not be an adequate assessment of the gastric mucosal barrier.
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PMID:Influence of acid secretory state on the gastric mucosal tolerance to back diffusion of H+. 0 31

Left ventricular performance was evaluated in seven canine right heart bypass preparations during and after the intraauricular administration of sodium bicarbonate (100 ml, 1100 Osm, 60 mEq). Under conditions of constant cardiac input and left ventricular volume, sodium bicarbonate produced mild and brief left ventricular depression, as manifested by a decline of left ventricular dp/dt with simultaneous rise of left ventricular end-diastrolic and left atrial pressures. These findings occurred as aortic impedance fell. Identical results accrued in paced and unpaced preparations. The data lends credence to the proposition that a sudden rise in blood pCO2 produces increased transport of CO2 across the cardiac membranes with intracellular acidosis. However, the data is also compatible with hyperosmolality induced contractile depression. Possible clinical implications are discussed.
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PMID:Effect of sodium bicarbonate on canine left ventricular function. 1 35

Sodium currents were studied under voltage clamp in the presence of neutral, amine, and quaternary local anesthetic compounds. Use-dependent block was observed as a cumulative depression of INa seen with repetitive depolarizing test pulses applied at frequencies of 2-10s-1. With quaternary QX-314, the time constant of use dependence was long, and with neutral benzocaine, very short. With lidocaine and procaine, increasing external pH (pHo) changed the time constant from long to short, but alterations of internal pH have no effect. Inactivation in Na channels was measured by the influence of prepulses on peak INa during test pulses. Single-stimulus inactivation curves were shifted more with lidocaine at high pHo than at low pHo, but inactivation curves measured during pulse trains with any of the drugs and at any pHo were strongly shifted. All measurements show that the drug-receptor reaction was slow for amine drugs at low pHo, as for quaternary drugs at any pHo, and fast for amine drugs at high pHo, as for neutral drugs at any pHo. The major effect of low pHo on amine drugs was to reduce the concentration of drugs in the fiber and to protonate drug molecules on the receptor, thus trapping them in the blocking position for a longer time. Direct effects of pH on the receptor seemed minimal.
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PMID:Local anesthetics. Effect of pH on use-dependent block of sodium channels in frog muscle. 2 11


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