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PubMed2004

Selective action of (-)-2-oxa-4-aminobicyclo[3.1.0]hexane-4,6-dicarboxylate (LY379268), a group II metabotropic glutamate receptor agonist, on basal and phencyclidine-induced dopamine release in the nucleus accumbens shell.

The effect of the group II metabotropic receptor agonist (-)-2-oxa-4-aminobicyclo[3.1.0]hexane-4,6-dicarboxylate (LY379268), on basal and phencyclidine-induced dopamine efflux were measured in the shell and core subdivisions of the nucleus accumbens--regions which are associated with limbic and motor functions, respectively. Extracellular levels of dopamine were measured using microdialysis in conscious animals, and LY379268 was delivered locally by inclusion in the artificial cerebrospinal fluid (aCSF) flowing through the microdialysis probe. Local administration of LY379268 in the concentration range 10 nM-10 microM reduced basal levels of dopamine in the nucleus accumbens shell, whilst having no effect in the nucleus accumbens core. In the nucleus accumbens shell, basal levels were reduced to approximately 60% compared to the pre-injection control, with a maximal reduction occurring at concentrations of LY379268 > or =100 nM. The response to LY379268 (100 nM) was reversible, with levels returning to baseline following its removal from the aCSF. In a separate experiment, local perfusion of the nucleus accumbens shell with LY379268 (at both 1 and 10 microM) reduced the magnitude of the response to a subsequent systemic administration of phencyclidine (5 mg/kg i.p.). The reduction in the peak dopamine response was only evident with doses of LY379268 that also reduced basal dopamine efflux--LY379268 being ineffective against PCP at 10 nM. However, in animals pre-treated with LY379268 at 1 or 10 microM, PCP still evoked a dopamine response, and in these animals the relative extent of the response was not significantly different between the respective treatment groups. In contrast, in the nucleus accumbens core the magnitude of the dopamine response to PCP was unaffected by local application of LY379268 (at 1 or 10 microM). Our data suggest that within the nucleus accumbens, there exists a distinct regional difference in the control of dopamine release by group II mGluRs, with the nucleus accumbens shell being preferentially affected. Moreover, the selective action of LY379268 on dopamine levels in the nucleus accumbens shell may have implications for the potential antipsychotic activity of group II mGluR agonists.

Amino Acids↗

PubMed2006

Effects of dorsal and ventral hippocampal NMDA stimulation on nucleus accumbens core and shell dopamine release.

This study has analysed the effects of infusing N-methyl-D-aspartate (NMDA) into either the ventral or dorsal hippocampus on dopamine (DA) transmission in the nucleus accumbens (NAC) core or shell for the first time. Dopamine was measured using in vivo microdialysis with high performance liquid chromatography with electrochemical detection (HPLC-EC). Unilateral NMDA infusion (0.5 microg) into the ventral hippocampus (VH) increased extracellular DA levels in NAC shell during the first 30 min following infusion compared to saline (SAL) infused animals. In contrast, NAC core DA levels were unaffected. NMDA infusion into the dorsal hippocampus (DH) led to a decrease in NAC core DA levels; this effect was not observed in the SAL-infused group. DA levels in NAC shell remained unaltered. At the end of the experiments, we examined the response to a systemic amphetamine (AMPH) injection of 1mg/kg on extracellular DA levels of the NAC core and shell. Interestingly, on2ly animals previously infused with NMDA into the VH exhibited a sensitized DA response in the NAC shell in response to the AMPH injection. We can conclude that VH activation has an acute stimulatory effect on DA release in the shell and that DH activation has a suppressive effect on extracellular DA levels in the core.

Amphetamine↗

PubMed2004

Morphine-induced alterations in gene expression of calbindin immunopositive neurons in nucleus accumbens shell and core.

Chronic opiate administration induces a number of biochemical alterations within the mesolimbic dopamine system that may mediate various aspects of the addictive process. In the present study, rats were administered morphine (1.0 mg/infusion) for 20 days (17.6+/-3.0 infusions/day) based on infusion histories of self-administering rats. Calbindin-D28K immunoreactive neurons were microdissected from the nucleus accumbens (NAc) shell and core subregions and gene expression was assessed using cDNA macroarrays. Comparison of gene expression between the shell and core subregions of vehicle-treated rats revealed significantly higher relative abundance of GABA-A alpha1, Galphai2 and post-synaptic density protein 95 transcript (PSD-95) mRNA levels in the shell, whereas Ggamma2 and synuclein 1 were more abundant in the core of the NAc. In the NAc shell, morphine administration resulted in upregulation of caspace 9, NF-kappaB, NF-H, tau, GABA-A delta subunit, FGFR1, Ggamma2, synuclein 1, syntaxin 5 and 13, GRK5, and c-fos mRNAs. Caspace 1, D2 dopamine receptor, GABA-A alpha1 subunit, GRIA 1/3/4, Galphai2, PSD-95 and CREB were down-regulated in the NAc shell with morphine administration. In the core, neuronal apoptotic inhibitory protein (NAIP), GABA-A alpha1 subunit, GRIN2C, GRIA1, mGluR1, D4 dopamine receptor and PSD-95 were upregulated by morphine administration whereas bax, bcl-x, cox-1 and MAP2 were decreased. These data demonstrate that morphine administration alters gene expression differentially in NAc subregions. Specifically, GABA-A alpha1 subunit, GRIA1 subunit and PSD-95 mRNAs were decreased in the shell but increased in the core following morphine administration. In addition, these results provide potential targets for further evaluation in models of morphine reinforcement as well as novel mechanisms of action in morphine-induced pathophysiology.

Animals↗

PubMed2003

Ultrasonic scattering cross sections of shell-encapsulated gas bubbles immersed in a viscoelastic liquid: first and second harmonics.

The oscillations of gas bubbles, without shell, immersed in viscoelastic liquids and driven by an acoustic wave have been the subject of several investigations. They demonstrate that the viscosity coefficient and the spring constant of the liquid have significant influence on the scattering cross section of the gas bubble. For shell-encapsulated gas bubbles, the investigations have been concentrated to bubbles immersed in a pure viscous liquid. This present work computes the ultrasonic scattering cross section, first and second harmonics, of shell-encapsulated gas bubbles immersed in a viscoelastic liquid. The theoretical model of the bubble oscillation is based on the generalized Rayleigh-Plesset equation of motion of a spherical cavity immersed in a viscoelastic liquid represented by a three-parameter linear Oldroyd model. The scattering cross section is computed for Albunex type of bubble (shell thickness=15 nm, shell shear viscosity=1.77 Pas, shell modulus of rigidity=88.8 MPa) irradiated by a 3.5 MHz ultrasonic pressure wave with an amplitude of 30 kPa. The results demonstrate that encapsulated bubbles respond independently of the surrounding liquid being pure viscous or viscoelastic as long as the surrounding liquid shear viscosity is as low as 10(-3) Pas. Nevertheless, for higher shear viscosities, the bubble responds differently if the surrounding liquid is pure viscous or viscoelastic. In general, the scattering cross sections of first and second harmonics are larger for the viscoelastic liquid.

Elasticity↗

PubMed1997

Loss of dopamine terminals in the medial prefrontal cortex increased the ratio of DOPAC to DA in tissue of the nucleus accumbens shell: role of stress.

We examined whether dopamine depletion in the medial prefrontal cortex of the rat differentially affects basal and evoked dopamine and 3,4-dihydroxyphenylacetic acid (DOPAC) content in the subareas of the neostriatum and nucleus accumbens. Loss of approximately 80% of tissue dopamine content in the medial prefrontal cortex did not significantly alter basal tissue concentrations of dopamine or DOPAC or the DOPAC:dopamine ratio in either the nucleus accumbens core or shell or the medial or lateral neostriatum. However, tail pressure stress significantly increased the DOPAC:dopamine ratio in the nucleus accumbens shell of lesioned rats. Because dorsal and ventral areas of the medial prefrontal cortex preferentially innervate the core and shell, respectively, we sought to determine whether the selective effect of lesions on dopamine terminals in the shell of the nucleus accumbens are paralleled by greater dopamine loss in the ventral medial prefrontal cortex. 6-Hydroxydopamine decreased tissue concentrations of dopamine in both the dorsal (-74%) and ventral medial prefrontal cortex (-68%). In lesioned rats, few tyrosine hydroxylase-immunoreactive fibers remained in the dorsal medial prefrontal cortex whereas a dense innervation remained in the ventralmost area. The present data suggest that the influence of mesocortical dopamine neurons on the dopamine projection to the nucleus accumbens shell is expressed only under conditions of stress. Furthermore, lesion-induced alterations in dopamine neurons projecting to the nucleus accumbens shell are not due to a more extensive loss of dopamine terminals in the ventral than in the dorsal medial prefrontal cortex.

3,4-Dihydroxyphenylacetic Acid↗

PubMed1998

Origin of noradrenergic afferents to the shell subregion of the nucleus accumbens: anterograde and retrograde tract-tracing studies in the rat.

The nucleus accumbens (NAcc) can be subdivided into 'core' and 'shell' based on anatomical connections and histochemical markers. Previous studies have demonstrated dopamine-beta-hydroxylase immunoreactive (DBH-ir) fibers in the NAcc shell, but the source of these noradrenergic (NE) afferents has not been determined. Therefore, we have investigated in detail the anatomy of NE afferents to this subregion. Dual immunohistochemistry for DBH and substance P demonstrated numerous DBH-ir fibers in the caudal NAcc shell. Neurons projecting to the NAcc were identified with Fluoro-Gold (FG) or cholera toxin B (CTb) retrograde tracing and tyrosine hydroxylase (TH) immunohistochemistry. Single- and double-labeled neurons were observed in the A2 and A1 NE cell groups following FG injections into the caudal NAcc shell. Numerous FG and CTb single-labeled neurons were found in the rostral locus coeruleus (LC), subcoeruleus and pericoerulear dendritic region, with an occasional double-labeled neuron in the LC. Few labeled neurons were seen in the brainstem after FG injections into the NAcc core, consistent with the lack of DBH-ir in this subterritory. To confirm these results, injections of Phaseolus vulgaris leucoagglutinin or biotinylated dextran amine were made into the LC or nucleus tractus solitarius (NTS). Virtually no labeled fibers were observed in the NAcc following injections into central LC. However, fibers were observed in the NAcc shell after injections in the NTS. These results indicate that the primary source(s) of NE afferents to the NAcc shell is the A2 region of the NTS, with lesser contributions from A1 and LC.

Animals↗

PubMed2001

Concurrent production of chitin from shrimp shells and fungi.

Crustacean shells constitute the traditional and current commercial source of chitin. Conversely, the control of fungal fermentation processes to produce quality chitin makes fungal mycelia an attractive alternative source. Therefore, the exploitation of both of these sources to produce chitin in a concurrent process should be advantageous and is reported here. Three proteolytic Aspergillus niger (strains 0576, 0307 and 0474) were selected from a screening for protease activity from among 34 zygomycete and deuteromycete strains. When fungi and shrimp shell powder were combined in a single reactor, the release of protease by the fungi facilitated the deproteinization of shrimp-shell powder and the release of hydrolyzed proteins. The hydrolyzed proteins in turn were utilized as a nitrogen source for fungal growth, leading to a lowering of the pH of the fermentation medium, thereby further enhancing the demineralization of the shrimp-shell powder. The shrimp-shell powders and fungal mycelia were separated after fermentation and extracted for chitin with 5% LiCl/DMAc solvent. Chitin isolates from the shells were found to have a protein content of less than 5%, while chitin isolates from the three fungal mycelia strains had protein content in the range of 10-15%. The relative molecular weights as estimated by GPC for all chitin samples were in the 10(5) dalton range. All samples displayed characteristic profiles for chitin in their FTIR and solid-state NMR spectra. All chitin samples evaluated with MTT and Neutral Red assays with three commercial cell lines did not display cytotoxic effects.

Animals↗

PubMed2003

Gold nanolayer-encapsulated silica particles synthesized by surface seeding and shell growing method: near infrared responsive materials.

Gold nanolayer-encapsulated silica particles whose optical resonance is located in 750-900 nm spectral region were synthesized by combining Sn (tin)-surface seeding and a shell growing process. The synthesized composite particles can be potentially used in wide biological fields, due to biocompatibility and a well-known bioconjugation technique of gold layer. Sn atoms, which can act not only as a catalytic surface for reduction of gold but also as a linker between silica surface and gold nanoparticles, were chemically deposited on hydroxylated silica particles. Then, we introduced another reductant with gold chloride in order to produce a multilayer of Au shell. In the process, Au shells grew by the reduction of additional gold ions on the Sn-functionalized silica surface and resulted in the subsequent coalescence and growth of the deposited gold nanoparticles. Finally, a complete gold nanoshell was formed on the silica surface by the one-step method, without a repeated coating process. The deposition of a gold nanolayer on the silica particles was easily controlled by the concentration ratio of Sn-functionalized silica particles and gold chloride solutions. Transmission electron microscopy (TEM) images and optical extinction spectra clearly showed that gold nanolayers were successfully deposited on the silica surface by the novel method. As the gold colloids attached on the silica surface grew, their optical plasmon peak became red-shifted until complete a gold shell was formed. After the gold shell was completed, the optical plasmon resonance became blue-shifted and the extinction spectra were functions of a relative ratio of the core to shell thickness.

Journal Article↗

PubMed2003

Determining the size distribution of core-shell spheres and other complex particles by laser diffraction.

The goal of this work is to determine the size distribution of hollow glass spheres by laser diffraction, an experiment which involves measuring angle-dependent scattering of light from particles dispersed in a liquid. The proprietary software supplied with commercial instruments is not strictly applicable to our two-layer, glass-shell, hollow-core spheres because it requires that the particles have spatially homogeneous properties. We therefore developed Fortran code to compute the scattering from core-shell spherical particles. The results show that the scattering from representative hollow glass particles diverges from homogeneous sphere scattering when the radius decreases from 10 to 3 microm. Additionally, scattering measurements on two core-shell hollow glass powders were analyzed using the exact core-shell optical model and homogeneous sphere approximations. In both cases, the size distribution determined using the exact core-shell model differs from that determined using the homogeneous-sphere approximation when the distribution covers radii smaller than about 10 microm, as expected. The size distribution based on the exact core-shell optical model was determined using a new algorithm. Although the basic equations used in the algorithm have been published previously, they are developed here in a different form, which can be implemented using Fortran and MatLab routines available commercially and in the public domain. This algorithm could be used to determine the size distribution of other kinds of particles, such as cylindrical rods, as long as their angle-dependent scattering could be computed.

Journal Article↗

PubMed1989

Rapid shell vial culture and tissue histology compared with serology for the rapid diagnosis of cytomegalovirus infection in liver transplantation.

Sixty-six patients who had undergone 78 liver transplantations, with no detectable cytomegalovirus (CMV) infection before transplantation, were studied to assess the value of CMV serology compared with the rapid detection of the virus in shell vial cell cultures or histology for the diagnosis of (1) the first evidence of infection, (2) symptomatic disease, and (3) asymptomatic infection. Of 28 evaluable patients, shell vial cell culture assay and histologic findings provided the first evidence of CMV infection earlier in 22 (79%) or at the same time as the serologic response in 5 (18%). Serologic results yielded the first indication of CMV infection in only 1 of these 28 patients (3%). Of 17 evaluable transplantations in 15 patients in whom symptomatic invasive disease developed, shell vial culture or histology provided a laboratory diagnosis of CMV infection earlier or at the same time as serologic responses in 16 (94%). Similarly, shell vial culture or histology provided evidence of CMV infection in 10 of 11 patients (91%) who had asymptomatic CMV infection and remained asymptomatic. Urine surveillance cultures yielded the first evidence of CMV infection in 14 of 19 patients who initially had an asymptomatic infection, of which 6 became symptomatic. Culturing of the blood with use of the rapid shell vial technique showed that viremia preceded CMV organ involvement in 7 of 10 patients. We recommend culture by the shell vial assay as the most rapid and sensitive method of determining CMV infection in liver transplant patients.

Cytomegalovirus Infections↗

PubMed1999

Behavioural and neurochemical effects of cholinergic and dopaminergic agonists administered into the accumbal core and shell in rats.

The first goal of this study was to investigate whether turning behaviour elicited by unilateral injections of the cholinergic agonist carbachol into the shell of the nucleus accumbens differs from that elicited by similar injections into the core of this nucleus, and to compare the behavioural effects with the known effects of such injections of the mixture of the dopamine D1 and D2 receptor agonists SKF 38393 (5 microg) and quinpirole (10 microg). The second goal was to investigate whether these injections of carbachol produce neurochemical alterations in the ventrolateral striatum that differ from similar injections of the mixture of the dopamine D1 and D2 receptor agonists into these brain regions. Injections of carbachol into the shell produced predominantly (a) contralateral circling marked by normal stepping and running in wide circles during the initial 50 min and (b) postural asymmetry during the following 75 min; similar injections into the core produced (a) contralateral pivoting, namely pathological head-to-tail turning marked by abnormal hindlimb stepping during the initial 50 min and (b) postural asymmetry during the next 75 min. The postural asymmetry seen after the carbachol injections was closely associated with the drug-induced increase in the dopamine release measured by microdialysis in the ipsilateral striatum. Injections of the mixture of dopamine agonists into the shell, but not core, also produced pivoting. These shell injections increased the dopamine release in the ipsilateral striatum, and decreased it in the contralateral striatum. The relative increase in the ipsilateral striatum was closely associated with the drug-induced pivoting. The data show that stimulation of cholinergic and dopaminergic receptors in the shell and core elicit effects that vary according to the subregion of the nucleus accumbens. It is concluded that the accumbens-specific, cholinergic effects are mediated via substrates that differ from those involved in the shell-specific, dopaminergic effects.

2,3,4,5-Tetrahydro-7,8-dihydroxy-1-phenyl-1H-3-ben↗

PubMed1998

Field studies on imposex and organotin accumulation in the rock shell, Thais clavigera, from the Seto Inland Sea and the Sanriku region, Japan.

Field studies on imposex and organotin (butyltin and phenyltin) contamination in the Japanese molluscs (the rock shell, Thais clavigera, and the Pacific oyster, Crassostrea gigas) were conducted along the coast of both the Seto Inland Sea and the Sanriku region, Japan, during February-March 1996. The percentage occurrence of imposex in the rock shell, Thais clavigera, was still 100% at all sites surveyed (22 and seven sites in the Seto Inland Sea and the Sanriku regions, respectively). Observed values of the Relative Penis Length (RPL) index (%), defined as the ratio of mean penis length in females to that in males, exceeded 50 at many sites. Sterile individuals whose oviducts were blocked by vas deferens formation were also extensively observed. Tissue concentrations of organotin compounds in the rock shell and the Pacific oyster were higher than those from other areas of Japan. The degree of imposex (RPL index) was correlated with the sum of TBT and TPT concentrations in tissue of the rock shell. Less recovery from imposex in the rock shell and less amelioration of TBT pollution were observed, suggesting that organotin use in antifouling paints has still continued for vessels larger than 25 m in length and that it has influenced imposex symptoms in the rock shell.

Animals↗

PubMed2000

Turning in rats following intraaccumbens shell injections of amphetamine or eticlopride.

In recent years there has been interest in possible differential behavioral functions of the core and shell subregions of the nucleus accumbens. The present study compared the effects of accumbens core and shell injections of (+)-amphetamine on turning behavior in rats; the turning effects of the selective D2 antagonist (-)-eticlopride injected into the shell were also tested. Rats (n = 28) were implanted unilaterally with guide cannulae and subsequently tested for turning in seven 20-min sessions. Amphetamine (10.0 and 20.0 microg but not 5.0 microg/ 0.5 microl) elicited contralateral turning following injection into the shell, while the same doses into the core had no effect. In animals given systemic amphetamine (2.0 mg/kg), eticlopride (10.0 but not 1.0 or 0.1 microg/0.5 microl) injected into the shell region of the accumbens produced ipsilateral turning. These results suggest that the accumbens shell, but not the core, is a critical site for turning behavior.

Amphetamine↗

PubMed2001

X-ray and neutron scattering analyses of hydration shells: a molecular interpretation based on sequence predictions and modelling fits.

Solution scattering is a low resolution diffraction method that provides important structural data on proteins. The ability to model scattering curves by recourse to known crystal structures for proteins under study significantly improves the resolution (and the utility) of the method because of the strict constraints that the crystal structures impose. For these structure determinations, a molecular description of the effect of hydration shells is needed. In calibration studies used for X-ray scattering curve modelling, it has been reproducibly found that a hydration shell is required. In molecular terms, this results from the higher electron density of the hydration shell compared to that of bulk water, which then becomes similar to that of the protein. This is well represented by a level of 0.3 g H(2)O/g glycoprotein and a water molecule volume of 0.0245 nm(3). Procedures for the addition of a hydration shell to a sphere model of a protein are described. For neutron scattering fits, it is not necessary to incorporate a hydration shell, as to a good approximation this is not detectable. In molecular terms, this apparent absence of the neutron hydration shell results from the effect of proton exchange on the scattering densities of bulk water and bound water which causes these to be similar but different from that of the protein.

Models, Chemical↗

PubMed1999

Psychological stress selectively increases extracellular dopamine in the 'shell', but not in the 'core' of the rat nucleus accumbens: a novel dual-needle probe simultaneous microdialysis study.

In order to compare psychological stress-induced dopamine (DA) release in two subterritories (e.g. shell and core) of the nucleus accumbens of the same animal, a novel dual-needle microdialysis probe has been developed. The two needles were placed in the ipsilateral shell and core subterritories of the nucleus accumbens under pentobarbital anesthesia and 24 h later the microdialysis was started. Basal DA output was not significantly different between the shell and the core. Psychological stress for 20 min significantly increased extracellular DA levels in the shell of the nucleus accumbens, however, the levels of dopamine remained almost unaltered in the core. This finding suggests that DA transmission in the shell of the nucleus accumbens was selectively activated during psychological stress, and that the shell plays an important role in emotional responses. The results further show that microdialysis using the novel dual-needle probe could be very useful to differentiate neurochemical changes occurring in neighboring areas in the brain.

Animals↗

PubMed1997

Effects of dopamine depletion in the medial prefrontal cortex on the stress-induced increase in extracellular dopamine in the nucleus accumbens core and shell.

In the present study we examined whether depletion of dopamine in the medial prefrontal cortex alters the neurochemical activity of mesoaccumbens dopamine neurons and/or their behavioral correlate, motor behavior. Infusion of 6-hydroxydopamine (1 microgram) into the medial prefrontal cortex of rats pretreated with a norepinephrine uptake blocker produced a 70% loss of tissue dopamine, with relative sparing of the norepinephrine content (-23%) in that region. Using in vivo microdialysis, we monitored basal and evoked extracellular dopamine in the nucleus accumbens core and shell of control and lesioned rats. The concentration of basal extracellular dopamine in the nucleus accumbens core was similar in control and lesioned rats; however, basal dopamine efflux in the nucleus accumbens shell was approximately 30% higher in lesioned rats than in controls. Lesions did not alter the ability of systemic D-amphetamine (1.5 mg/kg, i.p.) to increase extracellular dopamine in the nucleus accumbens shell, in contrast, the dopamine depletion in the medial prefrontal cortex attenuated the amphetamine-induced increase in extracellular dopamine in the nucleus accumbens core, as well as the amphetamine-induced increase in locomotor activity. Lesions did not significantly alter the effects of tail pressure (30 min) on extracellular dopamine in the nucleus accumbens core. However, the depletion of dopamine in the medial prefrontal cortex potentiated the stress-induced increase in extracellular dopamine in the nucleus accumbens shell. These data demonstrate that mesocortical dopamine neurons influence (i) amphetamine-induced dopamine efflux in the nucleus accumbens core and (ii) stress-evoked dopamine efflux in the nucleus accumbens shell. It has been proposed that a disruption in the interaction between cortical and subcortical dopamine neurons is involved in the pathophysiology of schizophrenia. The present data raise the possibility that a disruption in the interaction between mesocortical dopamine neurons and dopamine neurons projecting to the nucleus accumbens shell is involved in those symptoms of schizophrenia that are influenced by stress.

3,4-Dihydroxyphenylacetic Acid↗

PubMed2002

Efficacy and safety of the soft-shell technique in cases with a hard lens nucleus.

PURPOSE: To evaluate the efficacy and safety of the soft-shell technique in reducing corneal endothelial cell damage during cataract surgery in patients with a hard lens nucleus. SETTING: Miyata Eye Hospital, Miyakonojo, Miyazaki, Japan. METHODS: Sixty eyes of 57 cataract patients with a hard lens nucleus (Emery-Little classification grade 3 or higher) had phacoemulsification using the soft-shell technique with Healon((R)) (sodium hyaluronate 1%) and Viscoat (sodium hyaluronate 3.0%-chondroitin sulfate 4.0%) (soft-shell group) or with Healon alone (control group). The visual acuity, intraocular pressure (IOP), flare intensity in the anterior chamber, central corneal thickness, and corneal endothelial cell density were evaluated postoperatively. RESULTS: There were no significant IOP elevations in either group. The mean central corneal thickness in the control group was 539 microm +/- 26.0 (SD) preoperatively and 578 +/- 52.0 microm 1 day after surgery; the increase was significant (P =.0154). There was no significant change in the central corneal thickness in the soft-shell group. There were no statistically significant differences between the 2 groups in uncorrected visual acuity, best corrected visual acuity, IOP, flare intensity in the anterior chamber, and central corneal thickness throughout the follow-up. The rate of endothelial cell loss 3 months after surgery was 6.4% +/- 9.6% in the soft-shell group and 16.3% +/- 9.8% in the control group (P =.0003). CONCLUSION: The results suggest that the soft-shell technique is safe and effective in protecting corneal endothelial cells during cataract surgery in patients with a hard lens nucleus.

Aged↗

PubMed2002

Effects of 5-HT(1B) receptor ligands microinjected into the accumbal shell or core on the sensitization to cocaine in rats.

The present study was designed to find out whether 5-HT(1B) receptors located in subareas of the nucleus accumbens played a role in cocaine sensitization in rats, and whether pharmacological activation of these receptors could modify this drug effect. Male Wistar rats implanted bilaterally with cannulae into the accumbens shell or core were microinjected with GR 55562 (an antagonist of 5-HT(1B) receptors) or CP 93129 (an agonist of 5-HT(1B) receptors). The rats, which were repeatedly (for 5 days) administered with cocaine (10 mg/kg) and then challenged with cocaine (10 mg/kg) after 5-day withdrawal period, showed significantly higher locomotor hyperactivity in comparison with the effect observed in saline-pretreated and cocaine challenged rats. GR 55562 (0.1-10 microg/side), administered for 5 days into the accumbens shell, but not into the core, prior to cocaine dose-dependently attenuated cocaine sensitization. When injected for 5 days into either the accumbens shell or core before cocaine, CP 93129 (0.1-10 microg/side) had no effect on the development of cocaine sensitization. To examine the effects of GR 55562 and CP 93129 on the expression of cocaine sensitization, the drugs were given acutely before a challenge dose of cocaine (10 mg/kg) on day 10. No change in cocaine sensitization was observed after injection of GR 55562 (0.1-10 microg/side) to the either accumbens subregion or after injection of CP 93129 (0.1-10 microg/side) into the core. However, an intra-accumbens shell injection of CP 93129 (10-30 microg/side) increased sensitization to cocaine, and this enhancement was attenuated after local injection of GR 55562 (1 microg/side). Our findings indicate that behavioral sensitization to cocaine may be modulated by 5-HT(1B) receptor ligands in the accumbens shell, but not into the core. They suggest that the inhibition of 5-HT(1B) receptors in the accumbens shell attenuates the development, whereas their pharmacological activation enhances the expression of cocaine sensitization.

Analysis of Variance↗