Characteristics of the action of psychostimulants on learning and memory in rats

The effects of intraperitoneal injections of psychostimulant drugs: centrophenoxine (50 mg/kg) and peptide analog of tuftsin TP-1 (300 micrograms/kg) on the processes of elaboration and retention of conditioned reflex have been experimentally studied. The animals were trained with food reward in 30 trials per day. Psychostimulant drugs or saline were injected after the 10th trial. The elaboration of conditioned reflex was continued 30 min later. The retention was tested 24 h, 7 and 30 days later. It was established that both drugs induce an increase in memory traces stability during 30 days. These findings provide direct evidence that psychostimulant drugs, centrophenoxine and peptide substance TP-1, when injected during consolidation phase can enhance memory storage processes.     

Psychopharmacologic spectrum of melanostatin

Experiments on cats revealed an emotiotropic action of melanostatin on the original spectrum of emotional reactivity, similar to the effects of L-DOPA and amantadin. The drug does not possess an antidepressant action proper but activates the aggressive-defensive behaviour in experimental reserpine depression and reduces the provocation-induced aggressive behaviour in experimental haloperidol depression. In reserpinized mice, it antagonizes reserpine hypothermia, increases muscle tone and eliminates ptosis. It decreases haloperidol-induced catalepsia. Melanostatin increases the brain level of dopamine and its metabolite, homovanilic acid.     

Amino acid sequence of neurotoxin II from the sea anemone Radianthus macrodactylus

Amino acid sequence of neurotoxin II isolated from the sea anemone Radianthus macrodactylus was determined by analysis of peptides obtained after its digestion with trypsin and staphylococcal proteinase. It is shown that the polypeptide chain of the toxin consists of 48 amino acid residues, including six cysteines.     

Acclimation or stress symptom? An integrated study of intraspecific variation in the clonal plant Aechmea bromeliifolia,a widespread CAM tank‐bromeliad

The clonal tank-bromeliad Aechmea bromeliifolia (Rudge) Baker was found in four different habitats in a restinga (vegetation mosaic on sandy coastal plains), of south-eastern Brazil. These habitats (swamp forest, dry forest, dry shrubland and herbaceous marsh) lie within a few hundred metres of each other along a gradient extending inland from the coast, and differ markedly in terms of light and flood regime. We compared ramet morphology, leaf anatomy and physiology, and population parameters to examine the amplitude of trait variation of this widespread species in the studied restinga. This integrated approach allowed us to examine which variation conferred acclimation and which was merely a stress symptom. A . bromeliifolia showed site-specific differences in abundance, distribution, rosette size and shape, leaf anatomical arrangement and photochemical efficiency (potential quantum yield; F _v/ F _m) during the day. Most of the variation found seemed to be related to the interaction of light and flooding. The lowest number and size of ramets at the exposed, dry shrubland was matched by a marked leaf photoinhibition, which suggested poor acclimation to local levels of light intensity and limited water supply. In the other habitats, the morpho-physiological parameters measured suggested adequate foraging behaviour and site acclimation.  © 2002 The Linnean Society of London, Botanical Journal of the Linnean Society, 2002, 140 , 391-401.