New remarkable sexually dimorphic miniature species of Hyphessobrycon (Characiformes: Characidae) from the upper Rio Tapajós basin.

A new miniature species of Hyphessobrycon is described from an affluent of the Rio Papagaio, tributary of the Rio Juruena, upper Rio Tapajós basin, Mato Grosso State, Brazil. The new species can be distinguished from its congeners by having a remarkable secondary sexual dimorphism in its live colouration (males are red and females yellow), well-defined and relatively narrow dark midlateral stripe extending from tip of snout to tip of middle caudal-fin rays, absence of humeral blotch, 15-18 branched anal-fin rays and five or six branched pelvic-fin rays. The sexually dimorphic colouration of the new species is briefly discussed regarding its temporal variation.

A name for the 'blueberry tetra', an aquarium trade popular species of Hyphessobrycon Durbin (Characiformes, Characidae), with comments on fish species descriptions lacking accurate type locality.

A new species of Hyphessobrycon is described from a tributary of the upper Rio Tapajós, Amazon basin, Mato Grosso, Brazil. Its exuberant colour in life, with blue to purple body and red fins, is appreciated in the aquarium trade. Characters to diagnose the new species from all congeners are the presence of a single humeral blotch, absence of a distinct caudal-peduncle blotch, absence of a well-defined dark mid-lateral stripe on body, the presence of 16-18 branched anal-fin rays, nine branched dorsal-fin rays and six branched pelvic-fin rays. A brief comment on fish species descriptions solely based on aquarium material and its consequence for conservation policies is provided.

Moenkhausia celibela: a new species from the Amazon basin, Brazil (Characiformes: Characidae).

A new species of Characidae, Moenkhausia celibela, is described from the Rio Amazonas at Santarém, Rio Maraú, several localities in the Rio Tapajós, Rio Curuá-Una, Rio Xingu and Rio Jari, all from the Amazon basin, Brazil. The new species is distinguished from its congeners, except species included in Géry's 1992 Moenkhausia lepidura group, by presenting a dark blotch on the upper caudal-fin lobe, and the lower lobe is hyaline or light grey. Moenkhausia celibela is distinguished from the species of the M. lepidura group by the absence of a humeral spot and the presence of a roughly triangular and dark spot at the caudal-fin base, extending posteriorly along the middle caudal-fin rays, and distinctly separate from the spot on the upper caudal-fin lobe.

Effect of pimozide on the increase of muscarinic receptors caused by mazindol and apomorphine in the rat cerebral motor cortex

The effects of pimozide, mazindol and apomorphine on muscarinic receptors in homogenates of rat cerebral motor cortex were measured by binding assays, using 3H-N-methylscopolamine (3H-NMS) alone as ligand (for the measurement of M1- and M2-like receptors) or in the presence of carbachol or pirenzepine for determination of M1- and M2-like receptors, respectively. Female Wistar rats (150g) were treated daily for one week with pimozide, a dopaminergic antagonist (10 and 20 mg/Kg, po, by gavage), or with apomorphine (1mg/Kg,ip). In another ser of experiments, animals were treated with pimozide and 30 min later with mazindol (10 mg/Kg, po, by gavage) or apomorphine. The drugs were administered daily for one week. Controls received the same volume of saline. 3H-NMS binding was increased from the control value of 418 ñ 17 ñ 42 fmol/mg protein by administration of mazindol (10mg/Kg) but binding was reduced to 360 ñ 11 fmol/mg protein upon administration of pimozide (20mg/Kg) plus mazindol (10mg/Kg. Similarly 10 mg/ Kg pimozide reduced the increase in M1-like receptors caused by mazindol from 262 ñ to 220 ñ 20 fmol/mg protein. Although 20 mg/Kg pimozide alone produced a decrease in M1-plus M2-like receptors (from 418 ñ 17 to 348 ñ 22 fmol/mg protein), its action was preferentially on M2-like receptors, decreasing them from 148 ñ 10 to o ñ 15 fmol/mg protein in the control and treated groups, respectively. At the higher dose, 20 mg/Kg pimozide also inhibited the 3 H-NMS binding (M1-plus M2-like receptors) in the presence of apomorphine (263ñ25 vs 418 ñ 17 fmol/mg protein...