METHYLPHENIDATE AND ATOMOXETINE TREATMENT DURING ADOLESCENCE IN THE SPONTANEOUSLY HYPERTENSIVE RAT: MECHANISMS UNDERLYING HIGH COCAINE ABUSE LIABILITY IN ATTENTION DEFICIT/HYPERACTIVITY DISORDER

Effects of pharmacotherapies for Attention Deficit/Hyperactivity Disorder (ADHD) on cocaine abuse liability in ADHD are not understood. Spontaneously Hypertensive Rats (SHR), an ADHD model, exhibited greater cocaine self-administration than control Wistar-Kyoto and Wistar rats. Methylphenidate, but not atomoxetine during adolescence enhanced cocaine self-administration in adult SHRs compared to controls. The mesocortical dopaminergic system, including medial prefrontal (mPFC) and orbitofrontal (OFC) cortices, is important for ADHD and cocaine addiction. Dopamine and norepinephrine transporter (DAT and NET) are molecular targets for methylphenidate, atomoxetine and cocaine action. In the current studies, SHR, Wistar-Kyoto and Wistar were administered methylphenidate (1.5 mg/kg/day, p.o.), atomoxetine (0.3 mg/kg/day, i.p.) or vehicle during adolescence (postnatal day 28-55). During adulthood (\u3e77 days), DAT and NET functions in mPFC and OFC were determined as neurochemical mechanisms and locomotor sensitization to cocaine, and impulsivity under differential reinforcement of low rates 30-second (DRL30) schedule were evaluated as behavioral mechanisms associated with greater cocaine self-administration in methylphenidate-treated SHRs. Maximal velocity of [3H]dopamine uptake (Vmax) by DAT and DAT cellular distribution in mPFC and OFC did not differ between vehicle-control, adult SHR, Wistar-Kyoto and Wistar. Methylphenidate increased DAT Vmax, but not cell-surface expression, in SHR mPFC. In contrast, atomoxetine decreased Vmax and cell-surface expression in SHR OFC. Compared to control strains, norepinephrine uptake by NET in the OFC was increased in vehicle-administered SHR; methylphenidate during adolescence normalized NET function in SHR OFC. Locomotor sensitization was greater in SHR compared to control, and was not altered by methylphenidate. Under DRL30, methylphenidate increased burst responses in adult SHR compared to vehicle control as well as methylphenidate-treated Wistar-Kyoto and Wistar, indicating increased impulsivity. Increased OFC NET function, increased impulsivity and cocaine sensitivity may be the neurobehavioral mechanisms associated with the increased cocaine self-administration in SHR. Increased mPFC DAT function may underlie the enhanced impulsivity and cocaine self-administration in SHR administered methylphenidate during adolescence. Decreased OFC DAT function from atomoxetine-treated SHR may explain the reduced cocaine self-administration relative to methylphenidate. Thus, methylphenidate during adolescence in ADHD may increase risk for cocaine abuse, while atomoxetine may represent a therapeutic alternative for at-risk adolescents with ADHD

Effect of methylphenidate treatment during adolescence on norepinephrine transporter function in orbitofrontal cortex in a rat model of attention deficit hyperactivity disorder

Attention deficit hyperactivity disorder (ADHD) is associated with hypofunctional medial prefrontal cortex (mPFC) and orbitofrontal cortex (OFC). Methylphenidate (MPH) remediates ADHD, in part, by inhibiting the norepinephrine transporter (NET). MPH also reduces ADHD-like symptoms in spontaneously hypertensive rats (SHRs), a model of ADHD. However, effects of chronic MPH treatment on NET function in mPFC and OFC in SHR have not been reported. In the current study, long-term effects of repeated treatment with a therapeutically relevant oral dose of MPH during adolescence on NET function in subregions of mPFC (cingulate gyrus, prelimbic cortex and infralimbic cortex) and in the OFC of adult SHR, Wistar-Kyoto (WKY, inbred control) and Wistar (WIS, outbred control) rats were determined using in vivo voltammetry. Following local ejection of norepinephrine (NE), uptake rate was determined as peak amplitude (Amax)× first-order rate constant (k-1). In mPFC subregions, no strain or treatment effects were found in NE uptake rate. In OFC, NE uptake rate in vehicle-treated adult SHR was greater than in adult WKY and WIS administered vehicle. MPH treatment during adolescence normalized NE uptake rate in OFC in SHR. Thus, the current study implicates increased NET function in OFC as an underlying mechanism for reduced noradrenergic transmission in OFC, and consequently, the behavioral deficits associated with ADHD. MPH treatment during adolescence normalized NET function in OFC in adulthood, suggesting that the therapeutic action of MPH persists long after treatment cessation and may contribute to lasting reductions in deficits associated with ADHD.UL1 TR000117 - NCATS NIH HHS; R01 DA011716 - NIDA NIH HHS; P50 DA005312 - NIDA NIH HHS; P50 DA05312 - NIDA NIH HHS; R01 DA11716 - NIDA NIH HH

Adolescent methylphenidate treatment differentially alters adult impulsivity and hyperactivity in the Spontaneously Hypertensive Rat model of ADHD

Impulsivity and hyperactivity are two facets of attention deficit/hyperactivity disorder (ADHD). Impulsivity is expressed as reduced response inhibition capacity, an executive control mechanism that prevents premature execution of an intermittently reinforced behavior. During methylphenidate treatment, impulsivity and hyperactivity are decreased in adolescents with ADHD, but there is little information concerning levels of impulsivity and hyperactivity in adulthood after adolescent methylphenidate treatment is discontinued. The current study evaluated impulsivity, hyperactivity as well as cocaine sensitization during adulthood after adolescent methylphenidate treatment was discontinued in the Spontaneously Hypertensive Rat (SHR) model of ADHD. Treatments consisted of oral methylphenidate (1.5mg/kg) or water vehicle provided Monday-Friday from postnatal days 28-55. During adulthood, impulsivity was measured in SHR and control strains (Wistar Kyoto and Wistar rats) using differential reinforcement of low rate (DRL) schedules. Locomotor activity and cocaine sensitization were measured using the open-field assay. Adult SHR exhibited decreased efficiency of reinforcement under the DRL30 schedule and greater levels of locomotor activity and cocaine sensitization compared to control strains. Compared to vehicle, methylphenidate treatment during adolescence reduced hyperactivity in adult SHR, maintained the lower efficiency of reinforcement, and increased burst responding under DRL30. Cocaine sensitization was not altered following adolescent methylphenidate in adult SHR. In conclusion, adolescent treatment with methylphenidate followed by discontinuation in adulthood had a positive benefit by reducing hyperactivity in adult SHR rats; however, increased burst responding under DRL compared to SHR given vehicle, i.e., elevated impulsivity, constituted an adverse consequence associated with increased risk for cocaine abuse liability.P50 DA005312 - NIDA NIH HHS; R01 DA011716 - NIDA NIH HHS; P50 DA05312 - NIDA NIH HH

Effect of methylphenidate treatment during adolescence on norepinephrine transporter function in orbitofrontal cortex in a rat model of attention deficit hyperactivity disorder

Attention deficit hyperactivity disorder (ADHD) is associated with hypofunctional medial prefrontal cortex (mPFC) and orbitofrontal cortex (OFC). Methylphenidate (MPH) remediates ADHD, in part, by inhibiting the norepinephrine transporter (NET). MPH also reduces ADHD-like symptoms in spontaneously hypertensive rats (SHRs), a model of ADHD. However, effects of chronic MPH treatment on NET function in mPFC and OFC in SHR have not been reported. In the current study, long-term effects of repeated treatment with a therapeutically relevant oral dose of MPH during adolescence on NET function in subregions of mPFC (cingulate gyrus, prelimbic cortex and infralimbic cortex) and in the OFC of adult SHR, Wistar-Kyoto (WKY, inbred control) and Wistar (WIS, outbred control) rats were determined using in vivo voltammetry. Following local ejection of norepinephrine (NE), uptake rate was determined as peak amplitude (Amax)× first-order rate constant (k-1). In mPFC subregions, no strain or treatment effects were found in NE uptake rate. In OFC, NE uptake rate in vehicle-treated adult SHR was greater than in adult WKY and WIS administered vehicle. MPH treatment during adolescence normalized NE uptake rate in OFC in SHR. Thus, the current study implicates increased NET function in OFC as an underlying mechanism for reduced noradrenergic transmission in OFC, and consequently, the behavioral deficits associated with ADHD. MPH treatment during adolescence normalized NET function in OFC in adulthood, suggesting that the therapeutic action of MPH persists long after treatment cessation and may contribute to lasting reductions in deficits associated with ADHD.UL1 TR000117 - NCATS NIH HHS; R01 DA011716 - NIDA NIH HHS; P50 DA005312 - NIDA NIH HHS; P50 DA05312 - NIDA NIH HHS; R01 DA11716 - NIDA NIH HH

Berry Weight, Quality and Cane Biochemistry Changes in Relation to Cane Thickness of Own-Rooted and Grafted 'Tas-A-Ganesh' Grape

A field trial was conducted to determine the effect of cane thickness on berry quality and other biochemical parameters in 'Tas-A-Ganesh' grape at National Research Centre for Grapes, Pune, during the year 2008- 2009. Average bunch weight increased with increase in cane diameter. Own-rooted vines of cane thickness <6mm sprouted earlier than thicker canes. TSS of berries decreased with increase in berry size. Berries on grafted vines recorded lower TSS than on own-rooted vines. Biochemical parameters such as content of reducing sugars, carbohydrat and phenols were higher in grafted vines of cane thickness >10mm. Results indicate that thicker canes either on their own roots or on grafted vines are superior for yield and yield components, as also for physical properties of bunches and berries and total carbohydrate content of the canes

Development of validated stability indicating assay method for the simultaneous estimation of hydrochlorothiazide Amlodipine besylate and Losartan potassium in combine dosage form

A Stability indicating Reverse-Phase liquid chromatographic method for the simultaneous estimation of HCTZ, LOSA and AMLO was developed. The chromatographic assay involves the use of SUPELCO LC-8-DB column (15 cm x 4.6 mm, 5 m) with a simple mobile phase composition of Buffer (monobasic Potassium Dihydrogen phosphate of 0.025 M having pH 3.7): Acetonitrile (60:40) at a flow rate of 1mL/min with U.V detection at wavelength of 232 nm. The method showed good linearity in the concentration range of 4-40 ?g/mL for HCTZ and 2-22 ?g/mL for AMLO and 15-150 ?g/mL for LOSA. The proposed method was also successfully applied to 20 tablets of marketed formulation (Trilopace). The developed method was successfully validated as per the ICH guidelines for following parameters. Accuracy, precision, ruggedness, robustness, system suitability tests, etc. The RSD for system precision was found to be 0.89-0.49 for HCTZ, AMLO, and LOSA and for method precision 1.0-1.4 for HCTZ, AMLO, and LOSA. The average percentage recoveries 99.75, 99.88, 98.93 for HCTZ, AMLO, LOSA which was in good agreement with labeled amount of Pharmaceutical formulation. The stability indicating capacity was tested by accelerated degradation of marketed formulation in acidic (0.1 N HCL), basic (0.1 N NaOH), , Oxidative (3% H 2 O 2 ), Thermal (80 0 C

Breeding French Bean (Phaseolus vulgaris L.) for Resistance to Rust (Uromyces phaseoli Reben Wint.)

French bean is an important legume vegetable grown for its tender, green pods for both fresh consumption and processing. Rust, caused by Uromyces phaseoli, limits successful cultivation of this crop. Popular varieties like Contender, Pant Anupama, Pusa Parvathi, Arka Komal, Arka Suvidha, etc., are susceptible to this disease. The french bean variety, Arka Bold, having resistance to rust was used in hybridization with Arka Komal, a popular bush variety with high yield and slender, long green pods but susceptible to rust. Inheritance studies indicated that resistance to rust was controlled by a single, dominant gene. Pedigree method of breeding was followed for incorporating rust resistance in to commercially cultivated varieties. Breeding lines with resistance to rust were selected to F2 generation onwards. These were advanced up to F7, wherein, a promising line, (Arka Bold x Arka Komal) 99-17-2-1-4-12-3, with resistance to rust with high pod yield and good pod quality was selected and named Arka Anoop and released for commercial cultivation

Effect of Canopy Management Practices during forward Pruning on Berry Development and Photosynthesis in Tas-A-Ganesh Grapes

Effect of canopy manipulation during forward pruning on berry development and photosynthetic parameters was studied in Tas-A-Ganesh grape grafted onto Dogridge rootstock. Canopy manipulation including shoot thinning, leaf removal, shoot thinning with leaf removal, and shoot pinching, was done after forward pruning. Significant differences were observed in yield and quality. Shoot thinning to about 40 shoots per vine, with removal of three basal leaves, resulted in significantly higher yield, followed by that in shoot thinning alone. Lowest yield was recorded in the Control. Leaf removal drastically reduced bunch development affecting berry weight, diameter and length compared to other treatments. Among different canopy manipulation treatments, higher average bunch weight was recorded in shoot thinning plus leaf removal, whereas, lowest bunch weight was recorded with leaf removal alone. At harvest, the amount of total soluble solids in berries was low in leaf removal at pre-bloom stage, but increased in the treatment of shoot thinning with leaf removal, at the same stage. Different canopy manipulation treatments had significant impact on photosynthesis and transpiration rates. Overall results indicated that canopy manipulation practices such as shoot thinning, to retain 40 shoots per vine with or without leaf removal, followed by pinching, can be recommended to grape growers