Daniel J Calvo

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The dopamine D4 receptor (D4R) has received considerable interest because of its higher affinity for atypical antipsychotics, the extremely polymorphic nature of the human gene and the genetic association with attention deficit and hyperactivity disorder (ADHD). Several efforts have been undertaken to determine the D4R expression pattern in the brain using(More)
Benzodiazepines (BDZs) are the most widely prescribed class of psychoactive drugs in current therapeutic use, despite the important unwanted side-effects that they produce such as sedation, myorelaxation, ataxia, amnesia, ethanol and barbiturate potentiation and tolerance. Searching for safer BDZ-receptor (BDZ-R) ligands we have recently demonstrated the(More)
1. The mechanisms of action of antagonists of the gamma-aminobutyric acid C (GABA(C)) receptor picrotoxin, quercetin and pregnanolone were studied. 2. Ionic currents (chloride), mediated through human homomeric GABA rho(1) receptors expressed in Xenopus oocytes, were recorded by two-electrode voltage clamp. 3. Dose-response (D-R) curves and kinetic(More)
We studied the functional activation of different polymorphic variants of the human dopamine D(4) receptors by the three major central monoamines, dopamine, noradrenaline and serotonin. Dopamine D(4) receptors carrying two (D4.2), four (D4.4) or seven (D4.7) repeats within the third intracellular domain were co-expressed with G protein-regulated inwardly(More)
Fifteen minutes after the initiation of swimming stress in the rat we observed a 50% increase in the number of [3H]RO 5-4864 binding sites in kidney and a 37% increase in the olfactory bulb, without change in affinity. The binding in heart and cerebral cortex remained unchanged after the stress. These results are discussed in relation to previous work on(More)
The long-term effects of the systemic administration of DSP4 (N-(2-chloroethyl)N-ethyl-2-bromobenzylamine hydrochloride), a selective noradrenergic neurotoxin, on the endogenous levels of monoamines and their metabolites and on alpha- and beta-adrenoceptors in selected brain regions of the rat were examined. After 7 days, DSP4 caused a marked reduction(More)
Chrysin (5,7-di-OH-flavone) was identified in Passiflora coerulea L., a plant used as a sedative in folkloric medicine. Chrysin was found to be a ligand for the benzodiazepine receptors, both central (Ki = 3 microM, competitive mechanism) and peripheral (Ki = 13 microM, mixed-type mechanism). Administered to mice by the intracerebroventricular route,(More)
The activity of many receptors and ion channels in the nervous system can be regulated by redox-dependent mechanisms. Native and recombinant GABA(A) receptors are modulated by endogenous and pharmacological redox agents. However, the sensitivity of GABA(C) receptors to redox modulation has not been demonstrated. We studied the actions of different reducing(More)
A group of 35 wild Saccharum complex clones, collected in Laos(ECL), was studied for its nuclear genetic diversity by RFLP revealed by 10dispersed low copy probes. Representatives of the main germplasmdiversity, regularly used in introgression, were also included. A preliminarycharacterisation of the new clones was performed by Erianthus specificprimers. A(More)