Poisoning by Indigofera lespedezioides in horses.

Poisoning by Indigofera lespedezioides is reported in horses in the state of Roraima, northern Brazil. The main clinical signs are anorexia, sleepiness, unsteady gait, severe ataxia, weakness, stumbling, and progressive weight loss. To induce the disease experimentally, a 7-year-old horse was introduced in a small paddock invaded by the plant. The first nervous signs were observed 44 days from the start of grazing. The animal was euthanized on day 59. No significant gross lesions were observed upon necropsies of the experimental horse as well as one spontaneously affected horse. Upon histologic examination neuronal lipofuscinosis was observed in the brain, cerebellum, and spinal cord. Wallerian-type degeneration was observed on some mesencephalic tracts. Neuronal and axonal degeneration and lipofuscinosis were observed on electron microscopy examination. Indospicine was detected in four samples of I. lespedezioides with concentrations ranging from 63 to 1178 µg/g whereas nitro toxins could be detected in only one of the samples at a concentration of 2.5 mg/g. In conclusion, poisoning by I. lespedezioides is very similar to those poisonings by Indigofera linnaei and Indigofera hendecaphylla. Based on the preponderance of indospince and lack of nitro toxins in the samples it is proposed that indospicine is the toxic compound responsible for the poisoning.

Trophic and proliferative perturbations of in vivo/in vitro cephalic neural crest cells after ethanol exposure are prevented by neurotrophin 3.

Neural crest cells (NCCs), a transient population that migrates from the developing neural tube, distributes through the embryo and differentiates into many derivatives, are clearly involved in the damage induced by prenatal exposure to ethanol. The aim of this work was to evaluate alterations of trophic parameters of in vivo (in ovo) and in vitro NCCs exposed to teratogenic ethanol doses, and their possible prevention by trophic factor treatment. Chick embryos of 24-30h of incubation were treated during 10h with 100mM ethanol, or 40 ng/ml Neurotrophin 3 (NT3), or 10 ng/ml Ciliary Neurotrophic Factor (CNTF), or ethanol plus NT3 or CNTF, or defined medium; then the topographic distribution of NCC apoptosis was assessed using a whole-mount acridine orange supravital method. Cultures of cephalic NCCs were exposed to the same ethanol or NT3, or CNTF treatments, or ethanol plus one of both trophic factors, or N2 medium. A viability assay was performed using the calcein-ethidium test, apoptosis was evaluated with the TUNEL test, and proliferative capacity after BrdU labeling. After direct exposure of embryos to 100mM ethanol for 10h, a high level of NCC apoptosis was coincident with the abnormal closure of the neural tube. These anomalies were prevented in embryos exposed to ethanol plus NT3 but not with CNTF. In NCC cultures, high cell mortality and a diminution of proliferative activity were observed after 3h of ethanol treatment. Incubation with ethanol plus NT3 (but not with CNTF) prevented NCC mortality as well as a fall in NCC proliferation. The consequences of direct exposure to ethanol expand data from our and other laboratories, supporting current opinion on the potential risk of alcohol ingestion (even at low doses and/or during a short time), in any period of pregnancy or lactation. Our in vivo/in vitro model encourages us to examine the pathogenic mechanism(s) of the ethanol-exposed embryo as well as the use of trophic factors for the treatment and/or prevention of anomalies induced by prenatal alcohol.

Distribution of NADPH-diaphorase in rat mesencephalon: a light and electron microscopical study.

NADPH-diaphorase is a useful technique to reveal NO producing neurons at light microscopic level (LM). A modification of the technique using the tetrazolium salt BSPT as substrate, is useful to study the ultrastructure of NO neurons. The aim of this work was to perform a detailed analysis of NADPH-diaphorase reactive neurons in rat mesencephalon both at light and electron microscopic levels. NADPH-diaphorase reactive neurons were observed in superior colliculus, in central gray matter, in dorsal and medial raphe and in the pedunculopontine tegmental nucleus using two histochemical techniques at LM. Electron microscopy showed deposits on membranes of the endoplasmic reticulum, Golgi apparatus and nuclear envelope of dorsal raphe neurons. Presynaptic and postsynaptic terminals showed deposits on membranous elements but postsynaptic terminals also showed deposits on the inner surface of their membranes. Further physiological studies are needed to clarify the meaning of the ultrastructural findings such as the putative interaction of NOS with postsynaptic proteins, receptors or membranous channels.

Distribution of NADPH-diaphorase in rat mesencephalon: a light and electron microscopical study

NADPH-diaphorase is a useful technique to reveal NO producing neurons at light microscopic level (LM). A modification of the technique using the tetrazolium salt BSPT as substrate, is useful to study the ultrastructure of NO neurons. The aim of this work was to perform a detailed analysis of NADPH-diaphorase reactive neurons in rat mesencephalon both at light and electron microscopic levels. NADPH-diaphorase reactive neurons were observed in superior colliculus, in central gray matter, in dorsal and medial raphe and in the pedunculopontine tegmental nucleus using two histochemical techniques at LM. Electron microscopy showed deposits on membranes of the endoplasmic reticulum, Golgi apparatus and nuclear envelope of dorsal raphe neurons. Presynaptic and postsynaptic terminals showed deposits on membranous elements but postsynaptic terminals also showed deposits on the inner surface of their membranes. Further physiological studies are needed to clarify the meaning of the ultrastructural findings such as the putative interaction of NOS with postsynaptic proteins, receptors or membranous channels.(AU)

Distribution of NADPH-diaphorase in rat mesencephalon: a light and electron microscopical study

NADPH-diaphorase is a useful technique to reveal NO producing neurons at light microscopic level (LM). A modification of the technique using the tetrazolium salt BSPT as substrate, is useful to study the ultrastructure of NO neurons. The aim of this work was to perform a detailed analysis of NADPH-diaphorase reactive neurons in rat mesencephalon both at light and electron microscopic levels. NADPH-diaphorase reactive neurons were observed in superior colliculus, in central gray matter, in dorsal and medial raphe and in the pedunculopontine tegmental nucleus using two histochemical techniques at LM. Electron microscopy showed deposits on membranes of the endoplasmic reticulum, Golgi apparatus and nuclear envelope of dorsal raphe neurons. Presynaptic and postsynaptic terminals showed deposits on membranous elements but postsynaptic terminals also showed deposits on the inner surface of their membranes. Further physiological studies are needed to clarify the meaning of the ultrastructural findings such as the putative interaction of NOS with postsynaptic proteins, receptors or membranous channels.

Stimulation of Na+,K+-ATPase activity in certain membranes of the rat central nervous system (CNS) by acute administration of desipramine (DMI).

1. The activities of ATPase in rat CNS were studied 3 hr after administration of the noradrenaline uptake inhibitor, desipramine (DMI: 10 mg.kg-1, i.p.). Na+K+-ATPase activity significantly increased after DMI in the whole particulate from hypothalamus and mesencephalus but no changes in frontal cortex or in pons-medulla oblongata areas were found. This increase was prevented when the animals were pretreated with the noradrenergic neurotoxic N-(2-chloroethyl)-N-ethyl-2-bromobenzylamine (DSP-4). 2. Purified membrane fractions from hypothalamus were obtained by differential and sucrose gradient centrifugation (0.8-1.2 M sucrose). It was observed that after DMI, Na+,K+-ATPase activity increased only in the membranous fraction lying at 0.9 M sucrose. 3. Mg2+- or Ca2+-ATPase activities were not modified by DMI treatment. 4. Citalopram, a specific serotonergic uptake inhibitor, did not affect ATPase activities. 5. The results obtained could indicate that DMI acute administration selectively stimulates Na+,K+-ATPase activity of certain membranes of the CNS after an increase in the concentration of the noradrenergic neurotransmitter in the synaptic gap.

Estudio citofotométrico e citoquímico dos neuronios do nucleo istmo de gallus gallus domesticus (L) / Cytophotometric and cytochemical study of the nucleo istmo neurons of the gallus gallus domesticus

O estudo citofotométrico e citoquímico dos neurônios do núcleo istmo de Gallus gallus domesticus (L) com um dia e quatro meses de desenvolvimento pós-natal foi realizado com dois processos: violeta cresilo e ferro coloidal e um citofotomicroscópio Zeiss-modelo SMPH-01 unido a computador digital PDP-12. A pesquisa mostrou as diferenças existentes entre os neurônios das duas zonas do núcleo istmo: pars magnocelular e pars parvicelular. Nos pintos como um dia, os neurônios da pars magnocelular säo escassos e com áreas citoplasmáticas e nucleares grandes. O núcleo é bem delimitado, claro e com posiçäo excêntrica. Os neurônios la pars parvicelular säo pequenos e numerosos, com núcleos redondos e nucleólos visíveis. A forma da célula é ovóide e apresenta o citoplasma corado intensamente com violeta cresilo. A distribuiçäo dos valores de densidade óptica no citoplasma dos neurônios muda na pars magnocelular e na pars parvicelular. As células do núcleo istmo säo mais escuras, apresentando valores de densidade óptica mnuito alto, nos pintos com quatro meses. A reaçäo com ferro coloidal é mais forte nos exemplares com quatro meses. Sobre os resultados foram aplicados método estatísticos que permitem determinar as diferenças significativas