Respective effects on locomotor activity of injections of 5, 7-DHT in median raphe nucleus and of 6-OHDA in the mesolimbic dopaminergic group area in the rat]

This experiment was performed in order to demonstrate that the locomotor hyperactivity provoked by a radiofrequency lesion of the ventral mesencephalic tegmentum-A10 DA group area was not due to a 5-HT fiber damage. Four groups of Rats were used. First groups II and IV received a 5, 7-DHT injection in the median raphe; groups I and III received the vehicle. Locomotor activity was measured in a circular corridor 10 and 30 days; no hyperactivity was obtained. Then the same groups received a 6-OHDA injection, bilaterally in the A 10 area (groups III and IV) or the vehicle (groups I and II); the activity was measured 10 days later: significant hyperactivity was obtained with groups III and IV, without statistical differences between these two groups. In conclusion (i) 5-HT neurons are not directly involved in the VMT-hyperactivity, (ii) the DA A 10 neurons seem to be a critical anatomical target for this symptom.     

Brain stem projections to the cerebral cortex in the rat.

By means of the HRP method it was shown that the entire cerebral cortex, but in greater proportion the frontal and posterior temporo-parietal regions, receive fibres from the dorsal and medial raphe nuclei and from the locus coeruleus. In contrast, the pars compacta substantiae nigrae and the tegmental area send projections to the motor and cingular areas respectively.     

Brain stem projections to the cerebral cortex in the rat

Summary By means of the HRP method it was shown that the entire cerebral cortex, but in greater proportion the frontal and posterior temporo-parietal regions, receive fibres from the dorsal and medial raphe nuclei and from the locus coeruleus. In contrast, the pars compacta substantiae nigrae and the tegmental area send projections to the motor and cingular areas respectively.     

Projections of bulbar reticular nuclei and raphe nuclei to lobules VI and VII of cat cerebellar cortex]

Injections of horseradish peroxidase were made in lobules VI and VII of the cerebellar vermis (in the Cat). Serial frontal sections of the brain stem reveal that the lateral and paramedian nuclei were essentially projected onto lobule VI, and the projections from the raphe nuclei onto lobule VII.     

Monoamine oxidase inhibition by d-amphetamine in ganglia and nerve endings

Summary The inhibition of monoamine oxidase (MAO) activity by d-amphetamine was measured in homogenates of cat superior cervical ganglion and nictitating membrane, using tyramine (TM) and noradrenaline (NA) as substrates. In both tissues, d-amphetamine was shown to be a competitive inhibitor of the oxidation of TM. The Ki for d-amphetamine, as a MAO inhibitor, was lower in the ganglia than in the peripheral nerve endings.Supported by a Contract from the National Research Council of Argentina (CONICET) (Res. 67/79).     

Failure of medial forebrain bundle or raphe ablation to alter the daily temperature rhythm of the rat.

The data presented in the present study suggest that neither the ascending noradrenergic fibres confined to the MFB nor the serotonergic fibres originating in or passing through the mesencephalic raphe are essential for periodicity in body temperature. Both control and experimental groups, i.e., rats subjected to medial forebrain bundle or raphe ablation presented circadian periodicity in body temperature and neither the phase, amplitude or overall mean of experimentals differed significantly from controls.     

The involvement of the renin-angiotensin system in the regulation of cell proliferation in the rat endometrium

Oestrogens are known to enhance angiotensin biosynthesis by increasing the elaboration of its precursor, angiotensinogen. On the other hand, we found that inhibition of angiotensin-converting enzyme (ACE) suppressed the proliferative response of the rat anterior pituitary gland to oestrogens. To answer the question whether the angiotensin system is involved in the control of the cell proliferation of the uterine epithelium, the effects of an ACE inhibitor, enalapril maleate, and of angiotensins II and IV, alone or together with losartan, an antagonist of angiotensin receptor type 1 (AT1), on endometrial epithelial cell proliferation have been studied. The experiments were performed on ovariectomized female Wistar rats. In the first experiment the animals were injected with a single dose of oestradiol benzoate or received an injection of solvent only. Half of the oestrogen-treated rats were injected additionally with enalapril maleate (EN, twice daily). The incorporation of bromodeoxyuridine (BrDU) into endometrial cell nuclei was used as an index of cell proliferation. It was found that oestradiol alone dramatically increased the BrDU labelling index (LI) of endometrial cell nuclei, and this effect was partially blocked by the simultaneous treatment with EN. In the second experiment, the animals were injected intraperitoneally with angiotensin II (AII), angiotensin IV (AIV) or saline, alone or together with losartan. It was found that AIV induced an increase in the LI in uterine epithelium, and this effect was not blocked by the simultaneous treatment with losartan. The increase in LI in uterine epithelium was also observed in the rats treated with AII and with losartan. These findings suggest an involvement of angiotensin IV in the control of uterine epithelium cell proliferation. Received 12 October 1998; received after revision 6 January 1999; accepted 2 February 1999     

Immunocytochemical characterization of vasotocin and mesotocin secretory systems in duck brain

The neural systems secreting vasotocin and mesotocin has been characterized in the Duck brain with indirect immunofluorescent techniques, using specific antisera. In the anterior preoptic region and in supraoptic and paraventricular nuclei, neurons producing vasotocine and neurons producing mesotocine have been identified separately. Only vasotocinergic neurons were localized in ectomammillary tract. Vasotocin--and mesotocin--containing axons together enter the median eminence, some of them crossed the internal zone of the median eminence before ending in the posterior lobe of the pituitary, whereas other axons of both classes entered the external layer of the rostral median eminence, in close contact with the capillaries of the hypophysial portal system.     

Failure of medial forebrain bundle or raphe ablation to alter the daily temperature rhythm of the rat

Summary The data presented in the present study suggest that neither the ascending noradrenergic fibres confined to the MFB nor the serotonergic fibres originating in or passing through the mesencephalic raphe are essential for periodicity in body temperature. Both control and experimental groups, i.e., rats subjected to medial forebrain bundle or raphe ablation presented circadian periodicity in body temperature and neither the phase, amplitude or overall mean of experimentals differed significantly from controls.     

Radioautographic identification of central monoaminergic neurons by local micro-instillation of tritiated serotonin or noradrenaline in cats]

Monoaminergic neurons in nuclei raphe dorsalis and locus coeruleus of the Cat may be visualized by radioautography after local micro-instillation of tritiated serotonin and noradrenaline. The concomitant administration of the appropriate tracer with the other biogenic amine in non radioactive form permits a specific identification of serotoninergic and catecholaminergic nerve cell bodies. A small contingent of presumptive serotoninergic neurons is thus demonstrated in the region of the locus coeruleus.     

Sleep and monoamines: differential radioautography of central neurons after systematic injection of tritiated 5-hydroxytryptophane (5 HTP 3H) or of dihydroxyphenylalanine (DOPA 3H)]

In normal cats 90 min. after the intravenous injection of 5 mg/kg of 5 HTP and 3H 5 HTP or DOPA and 3H DOPA a few reactive nerve cell bodies were identified by radioautography. On the contrary, 48 hrs. after p-chlorophenylalanin or subtotal lesion of raphe nuclei, these tracers showed numerous reactive neurons inside or outside the central monoaminergic systems.     

Renewal of pulmonary insoluble collagen in the adult rat]

Study of polymeric pulmonary collagen in adult Rats showed that about 70% of collagen was renewed with a half-time equal to 525 days. This value is to be compared with the median life-span of this rat strain, 890 days. The remaining 30% of polymeric collagen is renewed with a shorter half time, about 30 days.     

Demonstration of "hydroxylase" and "epoxide hydrase" activities in preparations of nucleoli isolated from rat liver]

Aryl hydrocarbon hydroxylase (AHH) activity and epoxyde hydrase (EH) activity have been found in Rat liver nucleoli obtained from untreated (C) and methylcholanthrene (MC) pretreated Rats. Electron microscopic observations of nucleolar preparations did not reveal significant contamination either by intact nuclei or by nuclear membranes. Very low but detectable activity of NADPH cytochrome C reductase was found in the nucleoli. Nucleolar preparations revealed little AHH activity (12-18 pmoles/min/mg). AHH was inducible by MC in nuclei but not in nucleoli. The presence of EH in nucleoli was demonstrated with phenanthrene 9,10-oxide (550-620 pmoles/min/mg) and benzopyrene 4,5-oxide (92-116 pmoles/min/mg). These values were lower than those obtained using intact nuclei. The addition of TCPO (10(-4) M) inhibited EH activity.     

Intensification of amphetamine-induced excitation by methysergide,a serotonergic receptor blocker

Summary Methysergide, a serotonergic receptor blocker, was studied to determine its effects against d-amphetamine-induced excitation as measured by convulsions elicited by handling in mice. Significant intensification (p<0.01) of the action of d-amphetamine was observed in mice. These results indicate that reduction in serotonergic activity in the central nervous system enhances excitation induced by d-amphetamine.This work was supported by the Pharmaceutical Manufacturer Association Starter Grant, No. 5 S01 RR 05654-06 and the Air Force Office of Scientific Research Grant. The authors are grateful to Ben Wiggins, Michael Wallace, Maria Salazar, and Sanford Futterman for their technical assistance. The authors are also grateful to Dr Boris Tabakoff for supplying the formula of the CSF used in this experiment and we are indebted to San Antonio College for the use of their computer facilities. Dr Blum is a Career Teacher in drug addiction sponsored by NIDA, grant No. 1-T01-DA00290-01.     

Effect of benzatropine on the O-methylation of striatal dopamine]

After treatment by nialamid, benztropine administered to Rats produced an increase in the level of 3-O-methyldopamine in the corpus striatum. It produced a slight increase in the level of striatal dopamine and no change in the level of norepinephrine. The monoamine oxydase and catechol-O-methyltransferase activities of remaining brain showed no variations by benztropine. The results suggest the possible involvement of striatal dopamine and its extraneuronally catabolism in the antiparkinsonian effect of benztropine.     

Autoradiographic analysis of the primary visual projections of a diurnal predator (Buteo buteo L.)]

Radioautographic analysis of the optic system of a Common Buzzard (Buteo buteo L.) show hypothalamic (Meier's areas 1, 2 and 3), thalamic (nuclei lateralis anterior, geniculatus lateralis ventralis, dorsolateralis anterior), pretactal (nuclei geniculatus lateralis pretectalis--or Kuhlenbeck's geniculatus lateralis dorsalis--superficialis synencephali, griseus tectalis and area pretectalis), tegmental (nucleus ectomammillaris) and tectal visual projections. A general survey of Common Buzzard optic structures suggest a certain preponderancy of tectofugal system on thalamofugal system. Centrifugal visual system is reduced.     

Effect of experimental diabetes on estradiol binding by the anterior pituitary and hypothalamus in ovariectomized rats

Summary In diabetic rats,³H-estradiol binding by the cytosol and nuclei of the anterior pituitary was lower than normal. Changes in affinity and receptor numbers were demonstrated by Scatchard analysis. Protein synthesis in diabetic pituitaries, however, was in the normal range.     

Autoradiographische Studien über die DNS-Synthese im Hypophysenvorderlappen der Ratte

Summary By autoradiographic studies with H³-thymidine it is demonstrated that the percentage of labelled nuclei is very low in the anterior pituitary of normal untreated rats and of rats 14 days after thyreoidectomy. Following castration, however, a marked increase of DNA-synthesizing cells occurs as well as an increase of mitotic figures.

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Mit Unterstützung durch die Deutsche Forschungsgemeinschaft und das Bundesministerium für Wissenschaftliche Forschung.     

Measurement of cyclic AMP in the islets of Langerhans of newborn rats. Effect of amino acids]

Radioimmunoassay of cyclic AMP (cAMP) in the islets of Langerhans from 48-64 h old Rats was performed after succinylation of the samples. cAMP was detected at 0.03 nM. The cAMP content of islets increases when L-arginine, L-lysine and L alanine are added together in the incubation medium at a concentration of 5-10 mM each. When phosphodiesterase is inhibited by theophylline the three amino acids considerably increase the cAMP content of islets. Thus an increase in cAMP content of the islets was observed with a concentration of amino acids which is efficient in stimulating the insulin and glucagon secretion.     

Elaboration of an in vivo model, in half life size, for aeronautical purposes]

Toxic effects of combustion products originating from plane cabin constituents are studied, in vivo, in Rats. The model associates an important combustion room, and an experience room containing eight revolving cages for Rats; these cages allow a remote control of the movements of the Rats which can be electrically stimulated and ejected. Such a device permits to study the incapacitance, i.e. the inability to move. For the combustion of a seat, without ventilation, incapacitation appears in 2 to 6 min. Biochemical screening demonstrates on increase of pCO2, carboxyhemoglobin and glycemia and a decrease of pO2.