[3H]Ketanserin Binding in Human Brain Postmortem

This study aimed at comparing the binding characteristics of [³H]ketanserin, a high-affinity serotonin 2A (5-HT_2A) receptor antagonist, in the prefrontal cortex, hippocampus and striatum of human brain post-mortem. The results indicated the presence of a single population of binding sites in all the regions investigated, with no statistical difference in maximum binding capacity (B_max) or dissociation constant (K_d) values. The pharmacological profile of [³H]ketanserin binding was consistent with the labeling of the 5-HT_2A receptor, since it revealed a competing drug potency ranking of ketanserin = spiperone > clozapine = haloperidol > methysergide > mesulergine > 5-HT. In conclusion, the 5-HT_2A receptor, as labeled by [³H]ketanserin, would seem to consist of a homogenous population of binding sites and to be equally distributed in human prefronto-cortical, limbic and extrapyramidal structures.     

Demonstration of human platelet β-adrenergic receptors using 125I-labeled cyanopindolol and 125I-labeled hydroxybenzylpindolol

The radioiodinated pindolol analogs ¹²⁵I-labeled cyanopindolol ([¹²⁵I]CYP) and ¹²⁵I-labeled hydroxybenzylpindolol ([¹²⁵I]HBP) have been used to study binding to human platelet β-adrenergic receptors. [¹²⁵I]CYP binds to a saturable class of binding sites on platelet membranes with a dissociation constant (K_d) of 14±3 pM and maximal binding capacity (B_max) of 18±4 fmol/mg protein. Binding of [¹²⁵I]CYP is reversible and is characterized by forward and reverse rate constants of 1.8·10⁷ s^?1·M^?1 and 3.8·10^?4 s^?1, respectively. [¹²⁵I]HBP binds to a saturable class of platelet membrane sites with a K_d of 50±10 pM and B_max of 32±6 fmol/mg protein. [¹²⁵I]HBP also binds to a saturable class of sites on intact platelets with a K_d of 58±14 pM and B_max of 24±4 molecules per platelet. Binding of [¹²⁵I]CYP and [¹²⁵I]HBP is stereospecifically inhibited by propranolol and epinephrine; the (?) stereoisomers are at least 50-times more potent than the (+) stereoisomers. Binding of both radioligands is inhibited by adrenergic ligands with a potency order of propranolol ? isoproterenol > epinephrine > practolol > norepinephrine > phenylephrine. These observations indicate that [¹²⁵I]CYP and [¹²⁵I]HBP bind to platelet sites which have the pharmacological characteristics of β-adrenergic receptors but which are not typical of either the β₁ or β₂ sub-type.     

Nuclear benzodiazepine binding: Possible interaction with thyroid hormone receptors

The biochemical and pharmacological properties of nuclear [³H]flunitrazepam in brain tissues were studied. Nuclear [³Hflunitrazepam binding is saturable for both central and peripheral binding sites. Inosine and hypoxanthine displace nuclear [³H]flunitrazepam binding with greater potency than the membrane [³H]flunitrazepam binding. Triiodothyronine (T₃) increases the maximum number of binding sites (B_max) of nuclear [³H]flunitrazepam binding in vitro while thyroxine (T₄) does not have any effect. Diazepam reduces the affinity of nuclear¹²⁵I-T₃ binding in vitro, while the B_max is not affected significantly. Mild digestion of chromatin, using micrococcal nuclease, reveals that a major portion of nuclear [³H]flunitrazepam binding sites are located on chromatin. These data suggest a functional role for nuclear benzodiazepine binding and a possible modulatory effect of benzodiazepines on T₃ binding with its nuclear receptors.     

Binding of β1-adrenoreceptor antagonist [3H]CGP 26505 in rat cerebral cortex and sinus atrial nodeantagonist [3H]CGP 26505 in rat cerebral cortex and sinus atrial node

Specific β₁-adrenoreceptors antagonist [³H]CGP 26505 binding was characterized in rat cerebral cortex and heart sinus atrial node. In both tissues [³H]CGP 26505 binding was maximal at 25°C, it was specific, saturable and protein concentration dependent. Scatchard analysis of saturation isotherms of specific [³H]CGP 26505 binding in cerebral cortex showed that [³H]CGP 26505 binds a single class of high affinity sites with a dissociation constant (K_D) of 1±0.3 nM and a maximal number of binding sites (B_max) of 40±2 fmol/mg of protein. In sinus atrial node, [³H]-CGP 26505 binds a single class of high affinity sites (K_D=1.9±0.4 nM, B_max=28±2 fmol/mg of protein).     

Effects of pentobarbital tolerance to and dependence on GABAB receptor binding

Effects of pentobarbital pellet implantation on [³H]baclofen binding in the frontal cortex of cerebellum of rat brains were examined. In the frontal cortex, pentobarbital tolerance caused an increase in the number of binding sites (B_max) without changing their affinity (K_D). Twenty-four hours after withdrawal of the pentobarbital pellets, there was a significant increase in the K_D and B_max values. Cerebellar binding, in contrast, was not significantly changed in any of the treatment groups. Addition of 1 mM of pentobarbital directly to binding assays using cortical membrane produced as increase in K_D without a change in B_max.In vitro, pentobarbital affected neither the K_D nor the B_max in the cerebellar [³H]baclofen binding. These results suggest that like the GABA_A receptor, [³H]baclofen binding to the GABA_B receptor in rat frontal cortex was affected by pentobarbital tolerance and dependence, and that there are regional differences in the properties of the GABA_B receptor.     

Optimal radioligand exchange conditions for measurement of occupied androgen receptor sites in rat ventral prostate

This study was undertaken to define optimal conditions for exchange of ³H-R-1881 with endogenous hormone bound to androgen receptor (AR) sites in homogenates of rat ventral prostate (RVP) of mature animals. To minimize inactivation of AR binding sites under exchange conditions, extracellular proteases present in RVP were removed by mincing and washing tissue fragments in a Ca²⁺-free cell culture medium (J-MEM) containing 1% casein, prior to homogenization in a TEDG buffer (50 mm Tris-maleate buffer, pH 7.4; 1.5 mm EDTA; 2.0 mm DTT; and 10% ($\text{v}\text{v}$) glycerol) containing 0.5 mm phenylmercuric sulfonyl fluoride (PMSF) and 1.0 mm sodium azide. Na₂MoO₄ (final concentration, 20 mm) was added to homogenate fractions which then were incubated at 0–4 °C for 1–5 days with a saturating concentration of ³H-R-1881 (20 nm) in the absence and presence of 2 μm radioinert R-1881. Heparin (200 μg/ml) was added to the incubation medium to “solubilize” nuclear chromatin. Free and bound R-1881 were separated by a hydroxylapatite (HAP) batch procedure. Using these conditions, it has been found that (i) incubation periods of 72–96 h at 0–4 °C were required to achieve maximal specific exchange binding of ³H-R-1881 (B_max) in total homogenates from normal intact rats. Heparin addition (200 μg/ml) did not change B_max and had little or no effect on the rate of exchange. Mean B_max was 6.7 ± 1.6 (SD) pmol ³H-R-1881/mg DNA. R-1881 exchange at 24 h of incubation was only about 40% of B_max. Nonspecific binding, a small fraction (<10%) of B_max, was near maximal at 2 h. Incubation at 15 °C gave similar R-1881 exchange values to those obtained at 0 °C during the first 24 h, but at 48 h and thereafter R-1881 binding markedly decreased. These B_max values in total homogenates of normal intact RVP are about 2.5 times greater than the AR values obtained in 1-day castrated rats, when compared on a DNA basis, (ii) Addition of gelatin (0.25%) to inhibit seminin activity had no effect on B_max. Deletion of either MoO₄^2? or PMSF from the standard exchange medium reduced B_max values ~20%; if both PMSF and MoO₄^2? were deleted, B_max was reduced to a greater extent (~35%). B_max was reduced (40%) when homogenates were prepared without preliminary J-MEM:casein pretreatment and incubated in standard exchange medium with PMSF and MoO₄^2?. (iii) Despite AR stabilization by MoO₄^2? and inhibition of protease activities during exchange incubation, AR inactivation increased exponentially, so that the maximal ³H-R-1881 binding value achieved at 96 h was estimated to represent about 50% of the AR sites originally present. (iv) The binding sites in total homogenates occupied by ³H-R-1881 at 24, 72, and 96 h of exchange exhibited steroid specificity characteristics of AR, as determined by competition studies with a wide variety of steroid hormones and analogues. Scatchard plots of ³H-R-1881 exchange binding in total homogenates of normal intact RVP incubated for 72 or 96 h indicated a single class of affinity sites with apparent K_d of 5 to 6 nm. (v) Sucrose density gradient centrifugation of homogenates incubated for 72 or 96 h showed that the specific ³H-R-1881 binding sites were distributed in two broad peaks associated with low-molecular-weight components. One with S value ~3.5 may be “activated” AR; the other near the top of the gradient (S < 1.6) may include meroreceptor forms of AR.     

Ca2+-Guanine Nucleotide Interactions in Brain Membranes. I. Modulation of Central 5-Hydroxytryptamine Receptors in the Rat

Abstract: The present study indicates that central 5-hydroxytryptamine (5-HT; serotonin) receptors can be modulated in opposite directions by Ca²⁺ and guanine nucleotides [guanosine triphosphate (GTP), β, γ-imidoguanosine 5′-triphosphate (GppNHp)]. Thus CaCl₂ (≥0.5 mm ) inhibited whereas GTP and GppNHp (10 μm ) stimulated the 5-HT-sensitive adenylate cyclase in the hippocampus of newborn rats. Both the affinity (K_d ^?1) and the number (B_max) of [³H]5-HT binding sites in hippocampal membranes from adult rats were increased in the presence of Ca²⁺ (≥0.25 mm ); GTP (≥0.1 mm ) and GppNHp (≥0.3; μm ) produced reverse effects. The efficacy of guanine nucleotides in inhibiting specific [³H]5-HT binding was counteracted by Ca²⁺: the addition of this cation (5mm -CaCl₂) to the assay mixture resulted in a 40-fold increase in the IC₅₀ for GTP; the IC₅₀ for GppNHp increased five-fold under the same condition. The examination of the respective effects of Ca²⁺ and of GTP on the specific binding of [³H]5-HT to various hippocampal membrane preparations (from developing rats, from subcellular fractions of adult tissues, and from adult rats after the selective degeneration of serotoninergic innervation in the forebrain) indicated that the amplitudes of the Ca²⁺-induced increase and of the GTP-induced decrease were generally correlated. This conclusion did not apply to striatal membranes of kainic acid-treated rats because [³H]5-HT binding sites persisting after the intrastriatal injection of kainic acid (i.e., half of the total number in striatal membranes from control rats) were markedly less affected by GTP but at least as responsive as control membranes to the Ca²⁺-induced increase. These data are compatible with the hypothesis of a possible coupling of some–but not all–[³H]5-HT binding sites to adenylate cyclase in the rat brain.     

Binding of a thromboxane A2/prostaglandin H2 agonist [H]U46619 to washed human platelets

The binding characteristics of [³H]U46619 to washed human platelets were studied. [³H]U46619 binding to washed human platelets was saturable and displaceable. Kinetic studies yielded a K_d of 11 ± 4 nM (n=4). Scatchard analysis of equilibrium binding studies revealed one class of high affinity binding sites with a K_d of 20 ± 7nM and a B_max of 9.1 ± 2.3 fmole/10⁷ platelets (550 ± 141 binding sites per platelet) (n=4). A number of compounds that act as either agonists or antagonists of the TXA₂/PGH₂ receptor were tested for their ability to inhibit the binding of [³H]U46619 to washed human platelets. The K_ds of the agonists and antagonists were similar to their potencies to induce or inhibit platelet aggregation. These data provide some evidence that [³H]U46619 binds to the putative human platelet TXA₂/PGH₂ receptor.     

Labelling of 5-Hydroxytryptamine3 Receptors with a Novel 5-HT3 Receptor Ligand, [3H]RS-42358–197

Abstract: RS-42358–197{(S)-N-(1-azabicyclo[2.2.2]oct-3-yl)-2,4,5,6-tetrahydro-1H-benzo[de]isoquinolin-1-one hydrochloride} displaced the prototypic 5-hydroxytryptamine₃ (5-HT₃) receptor ligand [³H]quipazine in rat cerebral cortical membranes with an affinity (pK_i) of 9.8 ± 0.1, while having weak affinity (pK_i < 6.0) in 23 other receptor binding assays. [³H]RS-42358–197 was then utilized to label 5-HT₃ receptors in a variety of tissues. [³H]RS-42358–197 labelled high-affinity and saturable binding sites in membranes from rat cortex, NG108–15 cells, and rabbit ileal myenteric plexus with affinities (K_D) of 0.12 ± 0.01, 0.20 ± 0.01, and 0.10 ± 0.01 nM and densities (B_max) of 16.0 ± 2.0, 660 ± 74, and 88 ± 12 fmol/mg of protein, respectively. The density of sites labelled in each of these tissues with [³H]RS-42358–197 was similar to that labelled with [³H]GR 65630, but was significantly less than that found with [³H]-quipazine. The binding of [³H]RS-42358–197 had a pharmacological profile similar to that of [³H]quipazine, as indicated by the rank order of displacement potencies: RS-42358–197 > (S)-zacopride > tropisetron > (R)-zacopride > ondansetron > MDL72222 > 5-HT. However, differences in 5-HT₃ receptors of different tissues and species were detected on the basis of statistically significant differences in the affinities of phenylbiguanide, and 1-(m-chlorophenyl)biguanide when displacing [³H]RS-42358-197 binding. [³H]RS-42358–197 also labelled a population (B_max= 91 ± 17 fmol/mg of protein) of binding sites in guinea pig myenteric plexus membranes, with lower affinity (K_D= 1.6 ± 0.3 nM) than those in the other preparations. Moreover, the rank order of displacement potencies of 15 5-HT₃ receptor ligands in guinea pig ileum was found not to be identical to that in other tissues. Binding studies carried out with [³H]RS-42358–197 have detected differences in 5-HT₃ receptor binding sites in tissues of different species and further underscore the unique nature of the guinea pig 5-HT₃ receptor.     

Human platelet alpha 2-adrenergic receptors: labeling with 3H-yohimbine, a selective antagonist ligand

³H-Yohimbine, a potent and selective pharmacological antagonist of α₂-adrenergic receptors, labeled human platelet membrane α₂-receptors with high affinity. Binding was rapid and reversible at 25°C. Both saturation and kinetic experiments indicated a single order of binding sites, with an equilibrium K_D value of 1.0–1.5 nM. Low Mg²⁺ concentrations increased the K_D for ³H-yohimbine without altering the B_max. The ³H-yohimbine site exhibited α₂-receptor specificity: (?)-norepinephrine and (?)-isoproterenol were 4.8 and 330 times less potent than (?)-epinephrine; (?)-catecholamines were 17–35 times more potent than corresponding (+)-catecholamines; the selective α₁-antagonist prazosin was 340 times less potent than yohimbine. Catecholamine agonists exhibited shallow curves in inhibiting ³H-yohimbine binding, with pseudo-Hill coefficients (n_H) of less than 1.0, whereas the n_H of antagonists was 1.0. No specific binding of ³H-prazosin to platelet membranes was observed, indicating the absence of α₁-receptors. ³H-Yohimbine labeled fewer platelet sites than did ³H-dihydroergocryptine under identical conditions (80 vs 130 receptors/ cell), and may be a more specific and useful antagonist probe of platelet α₂-receptors than ³H-dihydroergocryptine.     

Decreased 5-HT2C receptor binding in the cerebral cortex and brain stem during pancreatic regeneration in rats

The purpose of this study was to investigate the role of central 5-HT_2C receptor binding in rat model of pancreatic regeneration using 60–70% pancreatectomy. The 5-HT and 5-HT_2C receptor kinetics were studied in cerebral cortex and brain stem of sham operated, 72 h pancreatectomised and 7 days pancreatectomised rats. Scatchard analysis with [³H] mesulergine in cerebral cortex showed a significant decrease (p < 0.05) in maximal binding (B_max) without any change in K_d in 72 h pancreatectomised rats compared with sham. The decreased B_max reversed to sham level by 7 days after pancreatectomy. In brain stem, Scatchard analysis showed a significant decrease (p < 0.01) in B_max with a significant increase (p < 0.01) in K_d. Competition analysis in brain stem showed a shift in affinity towards a low affinity. These parameters were reversed to sham level by 7 days after pancreatectomy. Thus the results suggest that 5-HT through the 5-HT_2C receptor in the brain has a functional regulatory role in the pancreatic regeneration.     

Leukotriene B4 binding to human neutrophils

[³H] Leukotriene B₄ (LTB₄) binds concentration dependency to intact human polymorophonuclear leukocytes (PMN's). The binding is saturable, reaches equilibrium in 10 min at 4°C, and is readily reversible. Mathematical modeling analysis reveals biphasic binding of [³H] LTB₄ indicating two discrete populations of binding sites. The high affinity binding sites have a dissociation constant of 0.46 × 10⁻⁹M and B_max of 1.96 × 10⁴ sites per neutrophil; the low affinity binding sites have a dissociation constant of 541 × 10⁻⁹M and a B_max of 45.6 × 10⁴ sites per neutrophil. Competitive binding experiments with structural analogues of LTB₄ demonstrate that the interaction between LTB₄ and the binding site is stereospecific, and correlates with the relative biological activity of the analogs. At 25°C[³H] LTB₄ is rapidly dissociated from the binding site and metabolized to 20-OH and 20-COOH-LTB₄. Purification of neutrophils in the presence of 5-lipoxygenase inhibitors significantly increases specific [³H] LTB₄ binding, suggesting that LTB₄ is biosynthesized during the purification procedure. These data suggest that stereospecific binding and metabolism of LTB₄ in neutrophils are tightly coupled processes.     

Modulation of the serotonin S2-receptor in brain after chronic lithium

In vivo effects of chronic lithium administration on dopaminergic and serotonergic receptor binding were studied in the striatum and cerebral cortex of the rat. [³H]Domperidone was used as the ligand for the dopaminergic receptor, and [³H]ketanserin for the serotonergic system. Long-term ingestion of lithium (2–3 months) resulted in high levels of lithium in the cerebral cortex and significantly higher potassium levels; the sodium content remained at normal levels. The kinetic constants (K _d andB _max) of [³H]domperidone binding sites measured in the striatum did not show any deviation from control values, but the receptor concentration (B _max) of [³H]ketanserin binding sites was significantly reduced in the cerebral cortex of lithium-treated rats. The apparent dissociation constant (K _d) was not changed. The results indicate that the serotonergic component of the [³H]spiperone binding site, which we had previously found to be affected by chronic lithium treatment and which was shown by Peroutka and Snyder (1) to be the 5-HT₂ receptor, is selectively affected by lithium.Special Issue dedicated to Prof. Eduardo De Robertis.     

Day–night specific binding of 2-[125I]Iodomelatonin and melatonin content in gill, small intestine and kidney of three fish species

Some of melatonin’s (Mel) well-established physiological effects are mediated via high-affinity cell-membrane receptors belonging to the superfamily of G-protein-coupled receptors. Specific binding of ligand 2-[¹²⁵I]iodomelatonin, using membrane preparations from osmoregulatory tissues of flounder, rainbow trout and sea bream, together with Mel concentrations in the tissues and plasma were studied. The kidney, gill and small intestine samples were collected during the day and at night. The dissociation constants (K _d) and maximal binding densities (B _max) were calculated for each tissue at 11:00 and 23:00 h. The binding sites with K _d values in the tissues in the picomolar range indicated the high affinity. K _d and B _max values were tissue- and species-dependent. The GTP analogue [Guanosine 5′-O-(3-thiotriphosphate)] treatment significantly reduced the B _max value, indicating that the 2-[¹²⁵I]iodomelatonin-binding sites are probably coupled to a G-protein. No daily variations in K _d and B _max values were observed. These are the first studies of the presence of 2-[¹²⁵I]iodomelatonin-binding sites in the small intestine, kidney tubule and gill of fish. The data strongly suggest new potential targets for Mel action and the influence of Mel on water/ion balance in fish. The intestine seems to be a site of Mel synthesis and/or an active accumulation of the hormone.     

The alteration of serotonin binding sites in aged human brain

The $\text{in}$$\text{vitro}$ binding of [³H]serotonin ([³H]5-HT) to cerebral cortex from young and old adult humans was studied. With cortex from human males 23–29 years old, the binding of [³H]5-HT was a saturable process, and bound [³H]5-HT could be displaced by unlabeled 5-HT or by lysergic acid diethylamide (LSD). Two separate binding sites were discernible by Scatchard analysis. The dissociation constants were 7 nM (Kd₁) and 52 nM (Kd₂), and the total number of binding sites were 0.65 (n₁) and 2.06 (n₂) pmoles/mg protein, respectively. In cerebral cortex from aged humans (61–70 years old), the dissociation constant for [³H]5-HT binding was 198 nM, and the total number of binding sites were 4.78 pmoles/mg protein. The alteration of serotonin binding sites may be related to cerebral malfunction in old people, particularly to mental depression and sleep disturbances that commonly occur.     

The specific binding of the platelet-activating factor (PAF) receptor antagonist WEB 2086 and the benzodiazepine flunitrazepam to rat hepatocytes

Thieno-triazolodiazepines WEB 2086 and BN 50739 have been described as the potent PAF receptor antagonists. Binding of radiolabeled [³H]WEB 2086 has been widely employed to characterize PAF receptors in different cells. In a search for a PAF receptor in isolated rat hepatocytes, we discovered that the binding of [³H]WEB to rat hepatocytes was highly specific but had a relatively low affinity with a K_d of 113 nM and B_max of 0.65 pmol/10⁶ cells in freshly isolated cell suspension and K_d of 1.65 μM and B_max of 2.0 pmol/plate in cultured hepatocytes. No consistent specific binding of [³H]PAF itself was found in the same cell preparations. The binding of [³H]flunitrazepam in the presence of the peripheral type of benzodiazepine receptor antagonist Ro 5-4864 was saturated and exhibited a K_i of 3.8 nM and B_max of 3.5 pmol/plate. The central type of benzodiazepine receptor antagonist clonazepam also competed for the [³H]flunitrazepam binding, however with a much lower affinity. Various antagonists inhibited the binding of [³H]WEB 2086 with a rank order BN 50739⪢Ro 5-4864≥clonazepam. Interestingly, bicuculline, a specific antagonist of GABA(A) recognition sites, also significantly reduced the binding of [³H]WEB 2086. The binding of [³H]flunitrazepam was inhibited with a rank potency BN 50739⪢WEB 2086. Taken together, these findings suggest that the specific binding of PAF receptor antagonists WEB 2086 and BN 50739 in rat hepatocytes does not involve PAF receptors and occurs via peripheral benzodiazepine and, possibly GABA(A) receptor sites.     

Identification of nucleoside transport binding sites in the human myocardium

The role of nucleoside transport in ischemia-reperfusion injury and arrhythmias has been well documented in various animal models using selective blockers. However, clinical application of nucleoside transport inhibitors remains to be demonstrated in humans. It is not known whether human heart has nucleoside transport similar to that of animals. The aim of this study is to pharmacologically identify the presence of nucleoside transport binding sites in the human myocardium compared to animals.Myocardial tissue was obtained from guinea pig left and right ventricle, canine left ventricle, human intraoperative right atrium and human cadaveric right atrium and right and left ventricles. Myocardial preparations were obtained from tissue samples after homogenized and a differential centrifugation.Equilibrium binding assays were performed using [³H]-p-nitrobenzylthioinosine (NBMPR) at room temperature in the presence or absence of non-radioactive NBMPR or other nucleoside transport blockers such as p-nitrobenzylthioguanosine dipyridamole, lidoflazine, papaverin, adenosine and doxorubcine. From saturation curves and inhibition kinetics, we determined the relative maximal binding (B_max) and dissociation constant (K_d) of [³H]-NBMPR binding of human myocardial preparations.Results demonstrated that the fresh human myocardial preparations have a specific binding site for NBMPR with a B_max of 283 ± 32 fmol/mg protein and K_d of 0.56 ± 0.12 nM. These values are lower than those obtained from guinea pigs (B_max = 1440 ± 187 fmol/mg protein and K_d = 0.21 ± 0.03 nM) and canine atrium (B_max 594 ± 73 fmol/mg protein, and K_d = 1.12 ± 0.22 nM).Displacement kinetics studies revealed the relative potencies (of certain unrelated drugs as follow: p-nitrobenzylthioguanosine > dipyridamole > lidoflazine > pavaverine > Diltazam > adenosine > doxyrubicin. It is concluded that human myocardium contains an active nucleoside transport site which may play a crucial role in post-ischemic reperfusion-mediated injury in a wide spectrum of ischemic syndromes.     

Effects of Pharmacotherapy on Combat-Related PTSD,Anxiety, and Depression: A Systematic Review and Meta-Regression Analysis

ObjectivesTo estimate the effect of pharmacotherapy on PTSD, anxiety, and depression among combat veterans; to determine whether the effects varied according to patient and intervention characteristics; and to examine differential effects of pharmacotherapy on outcomes.ResultsPharmacotherapy significantly reduced (Δ, 95%CI) PTSD (0.38, 0.23-0.52), anxiety (0.42, 0.30-0.54), and depressive symptoms (0.52, 0.35-0.70). The effects of SSRIs and tricyclic antidepressants on PTSD were greater than other medications independent of treatment duration. The effect of SSRIs and tricyclic antidepressants were greater than other medications up to 5.2 and 13.6 weeks for anxiety and depression, respectively. The magnitude of the effect of pharmacotherapy on concurrently-measured PTSD, anxiety, and depression did not significantly differ.ConclusionsPharmacotherapy reduced PTSD, anxiety, and depressive symptoms in combat veterans. The effects of SSRIs and tricyclic antidepressants were greater for PTSD and occurred quicker for anxiety and depression than other medications.     

Characterization of phenylalkylamine binding sites in insect (Periplaneta americana) nervous system and skeletal muscle membranes

This study has identified specific, stereoselective phenylalkylamine (PAA, (±)- [³H]verapamil) binding sites of low-affinity and high-density in cockroach (Periplaneta americana) nervous system and skeletal muscle membranes. Scatchard transformation of equilibrium binding data revealed a single population of binding sites in both tissues with dissociation constants (K_d) of 273 nM and 377 nM and binding capacities (B_max) of 23 pmol·mg protein^?1 and 37pmol·mg protein^?1 for cockroach nervous tissue and skeletal muscle membranes, respectively. The PAA binding site in cockroach nervous tissue membranes was found to be dihydropyridine (DHP)-insensitive, whereas the corresponding site in cockroach skeletal muscle membranes was DHP-sensitive. This property of a DHP-sensitive PAA receptor distinguishes the binding sites identified in cockroach skeletal muscle from those in cockroach nervous tissue and indicates that pharmacologically distinct putative Ca²⁺ channel subtypes are present in insect nerve and muscle. © 1993 Wiley-Liss, Inc.     

Increase in Striatal [3H]Muscimol Binding Following Intrastriatal Injection of Kainic Acid: A Denervation Supersensitivity Phenomenon

The effect of intrastriatal microinjection of kainic acid (KA) on specific binding of [³H]muscimol to the particulate fractions obtained from corpus striatum (CS), globus pallidus (GP), substantia nigra (SN), and cerebral cortex (CC) was examined. Seven days after the unilateral intrastriatal microinjection of KA, the amount of specifically bound [³H]muscimol was significantly increased at the injected site, whereas no significant alteration of [³H]muscimol binding was found in GP, SN, or CC. Scatchard analysis of striatal binding revealed that microinjection of KA significantly increased the affinity (K_D) of GABA receptors on the injected (lesioned) side of the CS without affecting the total number of binding sites (B_max) therein. This significant increase in [³H]muscimol binding, however, was eliminated by pretreating particulate fractions from the CS with Triton X-100, a non-ionic detergent. No statistically significant difference in amounts of [³H]muscimol binding was detected when the preparations from the KA-treated and non-treated CS were preincubated with 0.05% Triton X-100, respectively. Scatchard analysis using CS preparations treated with 0.05% Triton X-100 revealed that the affinity of the GABA receptor was increased by treatment with Triton X-100, while the total number of binding sites (B_max) was unchanged by this treatment. These results suggest that neuronal degeneration produced by KA in vivo and pretreatment of particulate preparations with Triton X-100 in vitro may increase the amount of specifically bound [³H]muscimol to CS preparations by a similar molecular mechanism.