Keith J. Lookingland

Learn More
Dopamine D2-like receptors play an important role in the pharmacotherapy of psychotic disorders. Molecular and cellular techniques have identified distinct gene products (D2-long, D2-short, D3 and D4) displaying the D2 receptor pharmacology. However, the contribution of each subtype in antipsychotic effects of or their physiological role remain unclear.(More)
Tuberoinfundibular dopamine (TIDA) neurons are spared in Parkinson's disease (PD), a disorder that causes degeneration of midbrain nigrostriatal dopamine (NSDA) and mesolimbic dopamine (MLDA) neurons. This pattern of susceptibility has been demonstrated in acute complex I inhibitor-induced models of PD, and extrinsic factors such as toxin distribution,(More)
BACKGROUND We recently reported that arterial superoxide (O2-) is augmented by increased endothelin-1 (ET-1) in deoxycorticosterone acetate (DOCA)-salt hypertension, a model of low renin hypertension. Tetrahydrobiopterin (BH4), a potent reducing molecule with antioxidant properties and an essential cofactor for endothelial nitric oxide synthase, protects(More)
The purpose of this study is to demonstrate that sumanirole is a novel dopamine receptor agonist with high in vitro and in vivo selectivity for the D(2) receptor subtype. Sumanirole, (R)-5,6-dihydro-5-(methylamino)-4H-imidazo[4,5,1-ij]quinolin-2(1H)-one (Z)-2-butenedioate (1:1), is unique; it has greater than 200-fold selectivity for the D(2) receptor(More)
The purpose of the present study was to characterize dopaminergic D2 receptor-mediated regulation of catecholaminergic neurons in the diencephalon by examining the acute effects of the potent and selective D2 agonist quinelorane (LY163502; trans-(-)-5,5a,6,7,8,9,9a,10-octahydro-6-propylpyrimido [4,5-g] quinolin-2-amine dihydrochloride dihydrate) on(More)
The effect of the kappa opioid receptor agonist U-50,488 [trans-3,4-dichloro-N-methyl-N-[2-pyrrolindinyl)-cyclohexyl]-benze ne- acetamide] was examined on the activity of dopamine (DA) neurons comprising the nigrostriatal, mesolimbic, tuberoinfundibular and tuberohypophysial systems in the male rat brain under basal and stimulated conditions. DA neuronal(More)
Administration of gamma-butyrolactone (GBL), an anesthetic which reduces dopaminergic neuronal activity, decreased the concentration of the dopamine (DA) metabolite 3,4-dihydroxyphenylacetic acid (DOPAC) in the intermediate lobe of the pituitary gland, and increased alpha-melanocyte stimulating hormone (alpha MSH) concentrations in the serum of male rats.(More)
The efficacy of active immunization against GnRH as a non-invasive alternative to physical castration was assessed in Hereford × Angus bull calves. Calves were randomly assigned to 1 of 4 treatment groups; unimmunized calves (n = 8), bull calves actively immunized against GnRH (n = 30), or calves castrated at 3 months of age and either non-implanted (n = 9)(More)
The activity of incertohypothalamic, tuberoinfundibular, mesolimbic and nigrostriatal dopamine (DA) neurons was estimated by measuring the rate of turnover of DA (decline of DA after alpha-methyltyrosine) in brain regions containing the cell bodies and terminals of these neurons. Estradiol benzoate (25 micrograms/kg/day X 3; s.c.), markedly increased the(More)
The functional role of alpha-synuclein in the pathogenesis of Parkinson's disease (PD) is not fully understood. Systemic exposure of alpha-synuclein-deficient mice to neurotoxins provides a direct approach to evaluate how alpha-synuclein may mediate cell death in a common murine model of PD. To this end, wild-type and homozygous alpha-synuclein knock-out(More)