Sodium regulation of agonist binding at opioid receptors. II. Effects of sodium replacement on opioid binding in guinea pig cortical membranes

We have examined the effects of sodium on the binding of opioid agonists to mu-, delta-, and kappa-receptors in guinea pig cortical membranes. Concentration curves for sodium indicated that maximal inhibition of mu binding by this cation was about 60% and maximal inhibition for delta binding was about 70%, whereas that for kappa binding was only about 20%. The concentration of sodium required for half-maximal inhibition of binding to all three sites was about 10-30 mM, corresponding to the intracellular sodium concentration. The nature of the sodium effect was further characterized by saturation analysis of binding to each of the three receptor types by comparing results obtained in the presence of 120 mM sodium with those obtained with equimolar replacement of sodium by another cation. Two radiolabeled agonists with different structural characteristics were tested for each binding site. In the presence of sodium, the affinity of the labeled agonists for mu sites was approximately 2-3-fold less than in its absence, but the density of binding sites was not changed. At kappa sites, sodium reduced agonist affinity slightly but, again, did not alter the number of binding sites. In contrast, sodium reduced the apparent density of delta-binding sites while leaving the agonist affinity unchanged. Competition against antagonist binding to delta sites indicated that, in the presence of sodium, a higher proportion of sites was in a lower affinity state, as reflected by the biphasic nature of the agonist displacement curve. In contrast, the effect of sodium on displacement of antagonist from mu sites was to of sodium on displacement of antagonist from mu sites was to lower the affinity of the agonist. Competition against antagonist binding to kappa sites also showed a reduction in agonist affinity by sodium, but no change in number of receptors. The results indicate that sodium may differentially regulate agonist binding to opioid receptor types and that this regulation may occur at an intracellular site. The kappa site appears to be less sensitive to sodium than the mu and delta sites.

Sodium regulation of agonist binding at opioid receptors. I. Effects of sodium replacement on binding at mu- and delta-type receptors in 7315c and NG108-15 cells and cell membranes

The effects of varying the sodium concentration (at constant ionic strength) on opioid binding at mu- and delta-opioid receptors in 7315c and NG108-15 cells has been examined. The binding of [3H]etorphine to mu-receptors on 7315c cells was increased by replacing the sodium in the incubation medium with potassium or N-methyl-D-glucamine. This effect was shown to be attributable to an increase in affinity, with no change in the maximum number of binding sites, both in cell membrane suspensions and in intact 7315c cells. Replacement of sodium with potassium or N-methyl-D-glucamine in NG108-15 membrane or intact cell suspensions also resulted in an increase in [3H]etorphine binding, but in these cells the effect was associated with an increase in the number of binding sites measurable under these experimental conditions. The effects of sodium on opioid inhibition of adenylate cyclase in membrane preparations from 7315c and NG108-15 cells also differed. Sodium reduced apparent agonist affinity in 7315c membranes. In NG108-15 cell membranes, sodium was essential for the demonstration of opioid inhibition of cyclase activity. Increasing the sodium concentration above 0.5 mM resulted in an increase in the fraction of total enzyme activity inhibited by opioid, but the opioid IC50 did not change. In the companion paper, it is shown that the effects of sodium removal on mu- and delta-receptor binding in guinea pig brain neural membranes were similar to those observed in the cell preparations. An increase in intracellular sodium concentration without change in extracellular concentration was effected by incubation of 7315c and NG108-15 cells with the sodium-selective ionophore, monensin. When sodium was present in the extracellular medium, monensin reduced [3H]etorphine binding by 50% or more, both at mu-receptors in 7315c cells and at delta-receptors in NG108-15 cells. In the absence of sodium, however, monensin treatment produced only a small inhibition of binding. These results suggest that sodium acts at an intracellular site to regulate opioid agonist binding at both mu- and delta-receptors, but that the mode of regulation is not identical at each site. Since a reduction in intracellular sodium concentration by removal of extracellular sodium increases agonist binding, and an increase in intracellular sodium following monensin treatment reduces agonist binding, it is probable that the intracellular sodium concentration is a critical regulator of opioid agonist binding in intact cells.

Globus hystericus syndrome responsive to antidepressants

Three patients with globus hystericus responded to antidepressant medication. The authors discuss the syndrome's relationship to major depression, its diagnostic classification, and its treatment.

Opioid ligand binding sites in the spinal cord of the guinea-pig

The properties of opioid binding sites in membranes from the spinal cord of the guinea-pig were analyzed in experiments employing radiolabeled opioid ligands, selective or partially selective for mu, delta and kappa-type binding sites. Incubation was conducted at 37 degrees C in a quasi-physiological modified Krebs medium, containing sodium and magnesium. The types of binding sites were discriminated on the basis of their affinities for [3H-D-Ala2-MePhe4-Gly5-ol]enkephalin ([3H]DAGO), [3H-D-Ala2-D-Leu5]enkephalin, and [3H]ethylketocyclazocine and the relative potencies of the displacing ligands, DAGO, [D-Ser2-Leu5]enkephalyl-Thr and trans-3,4-dichloro-N-methyl-N-[2-(1-pyrrolidinyl)- cyclohexyl]benzeneacetamide methanesulfonate hydrate (U50488H), which are selective for mu, delta and kappa type binding sites respectively. In membranes from whole spinal cord, kappa type sites comprised about 60%, mu about 30% and delta about 10% of the total of mu, delta and kappa binding sites. Binding sites of the mu type were also found in the lumbo-sacral region of guinea-pig spinal cord, in contrast to earlier reports of their absence from this tissue. Morphine showed a better than 500-fold selectivity for mu over kappa sites in spinal cord, while nalbuphine and (-)1-cyclopentyl-5-(1,2,3,4,5,6-hexahydro-8-hydroxy-3,6,11- trimethyl-2,6-methano-3-benzazocin-11-yl)3-pentanone methanesulfonate (WIN 44441-3) showed about a 10-fold selectivity for mu sites. The drug U50488H had about a 150-fold greater affinity for kappa than mu-type binding sites.

Opioid binding to rat and guinea-pig neural membranes in the presence of physiological cations at 37 degrees C

We have identified mu, delta and kappa opioid binding sites in four types of neural membranes under conditions which include physiological concentrations of ions and an incubation temperature of 37 degrees C. We hypothesize that binding parameters determined under these conditions should be more directly comparable with physiological experiments than parameters obtained under conditions of low ionic concentration and at low temperature. By using either a radioligand which is selective for a single type of opioid binding site or a relatively nonselective radioligand in the presence of an unlabeled selective ligand, we have isolated binding to single populations of sites. Saturation and displacement data were analyzed with the aid of a computerized nonlinear curve fitting program. [3H]Tyr-D-Ala-Gly-(Me)Phe-Gly-ol bound to a single population of sites with the characteristics of mu receptors, as determined by saturation and displacement analysis. Binding to the mu site represented 70% of the total specific opioid binding in rat brain, but only 20 to 30% in guinea-pig tissues. [3H][D-Ala2-D-Leu5]enkephalin bound almost equally well to mu and delta sites, but the delta site could be examined by the inclusion of unlabeled Tyr-D-Ala-Gly-(Me)Phe-Gly-ol in the incubations. [3H]Ethylketocyclazocine bound mu and kappa sites, and Tyr-D-Ala-Gly-(Me)Phe-Gly-ol was also used to block the mu component in experiments in which we studied kappa binding. Binding to kappa sites represented 50 to 60% of the total in guinea-pig tissues, but less than 20% in rat brain.

Clinical aspects of experimentally induced chloride deficiency in Holstein calves

A severe total body chloride deficit was induced in Holstein calves by feeding a low-chloride ration (0.063% Cl) and removing digesta daily from the abomasum through a surgically implanted cannula. Clinical signs of the deficit observed included polydipsia, polyuria, dehydration, anorexia, scleral injection, decreased respiratory rate, and blood and mucus in the feces. Necropsy findings included dehydration, blood in the lumen of the small intestine, and renal lesions. The most extensive histopathologic changes occurred in the renal tubular epithelium of the outer medulla where mineralization of the tubular epithelium and basement membranes was frequently seen.

Systemic and renal effects of angiotensin II in the freshwater turtle Pseudemys scripta elegans

This study examined the renal and systemic effects of angiotensin II (ANG II) in the freshwater turtle, Pseudemys scripta elegans. We infused [Asn1, Val5]ANG II at doses of 1, 10, 100, and 500 ng X kg-1 X min-1 in conscious turtles while monitoring blood pressure, glomerular filtration rate (GFR), urine volume, and plasma and urine electrolytes. Saline (0.6%) was infused for two 1-h control periods at 1 ml X kg-1 X h-1 followed by a 1-h infusion of saline with ANG II added. Saline alone was then infused for either two or three 1-h recovery periods. Control values before ANG II infusion averaged 21 mmHg for blood pressure, 1.8 ml X h-1 for urine volume, and 8.0 ml X kg-1 X h-1 for GFR. At 1 (n = 7) and 10 ng X kg-1 X min-1 (n = 6) ANG II produced no significant changes in blood pressure or renal function. Angiotensin infusion at the higher rates of 100 (n = 6) and 500 ng X kg-1 X min-1 (n = 11) significantly elevated blood pressure during ANG II infusion (29 and 44 mmHg, respectively), while electrolyte excretion remained unchanged. Despite the increased blood pressure, GFR and urine volume tended to decrease. At all infusion rates, plasma electrolytes remained unchanged. The results suggest that ANG II is a potent constrictor of preglomerular vessels in the kidney of the turtle.

Feldenkrais versus conventional exercises for the elderly

Tenants in retirement housing given a 6-week program of Feldenkrais exercises were compared with a group given conventional exercises and with control groups given no exercises. Analysis of covariance of preliminary and subsequent measurements failed to yield any significant differences between groups. Measurements included height, weight, blood pressure, heart rate, balance, flexibility, morale, self-perceived health status and level of performance of activities of daily living, also the number of body parts difficult to move or giving rise to pain. Several possible reasons are given for the results. Attention is drawn to the necessity of medically screening and monitoring elderly registrants for exercise programs since it is apparent that some sign up who should not.

Interactions of CNS drugs--hypnotics and sedatives

The physicochemical properties of the barbiturates and a brief review of microsomal enzyme induction introduces this literature review of the interactions of sedative and hypnotic drugs. Food has been shown to delay absorption of barbiturates; barbiturates, in turn, may interfere with the absorption of griseofulvin, dicumarol, and folic acid. Barbiturate-produced enzyme induction may result in interactions with the oral anticoagulants, the anticonvulsants, vitamin D, bilirubin, digitoxin, doxycycline, and perhaps other drugs. The problem of additive central nervous system depression and the relative lack of documented evidence is considered. Finally, the interactions of nonbarbiturate hypnotics, such as glutethimide, chloral hydrate, and others are reviewed.

Bibliography on Q technique and its methodology

More than 580 references on Q technique and its methodology are grouped in the following categories: [1] History, Principles, Controversies, and Evaluation; [2] Factor Analysis and Related Statistics; [3] Measurement Theory: (a) Nonprojective tests and assessment, (b) Application to projective tests, (c) Q sort tests; [4] Applications of Q Technique: (a) Self psychology, (b) Counseling and psychotherapy, (c) Personality theory and research, (d) Type psychology, (e) Clinical psychology, (f) Educational and child psychology, (g) Social relations and social science; [5] Contributions of William Stephenson; [6] Reviews; and [7] Unpublished Materials and Manuals. A brief essay precedes the bibliography.