Functional aspects of serotonin transmission in the basal ganglia: a review and an in vivo approach using the push-pull cannula technique

Peripheral deafferentation of the rodent olfactory bulb results in loss of dopamine content, tyrosine hydroxylase activity and immunocytochemical staining for tyrosine hydroxylase in juxtaglomerular dopamine neurons. Reinnervation of the bulb by afferent neurons results in the return of all parameters to control levels suggesting that the dopamine neurons did not degenerate but that the expression of tyrosine hydroxylase enzyme was transneuronally regulated in a static population of juxtaglomerular cells. To evaluate this possibility, we determined the activity and immunocytochemical localization of the second enzyme in the dopamine biosynthetic pathway, DOPA decar?ylase. At a time when tyrosine hydroxylase activity was reduced to 25% of control values, DOPA decar?ylase activity in the lesioned bulb was maintained at about 65% of that in the unlesioned bulb. Immunocytochemical staining with antibodies to both enzymes, performed sequentially in the same sections, demonstrated that in the unlesioned bulb tyrosine hydroxylase and DOPA decar?ylase are co-localized in the same population of juxtaglomerular neurons. Similar results were obtained in adjacent sections each stained with one of the two antibodies. In contrast, in the deafferented bulb, about three times as many neurons were stained with DOPA decar?ylase as with tyrosine hydroxylase antibodies. The DOPA decar?ylase activity measurements and immunocytochemistry argue for the continued presence, in the lesioned olfactory bulb, of a population of tyrosine hydroxylase deficient dopamine neurons.The data suggest that olfactory receptor cell innervation transneuronally regulates the expression of tyrosine hydroxylase by mechanisms separate from those controlling the levels of DOPA decar?ylase.     

Disturbances of cell-mediated immunity in ornithosis

27 cases of ornithosis were observed during an epidemia in 1980 in Kielce and subsequently followed with respect to immunological characteristics of peripheral blood lymphocytes. Blastic transformation of these cells was tested after stimulation in vitro with three different mitogens. Identification of peripheral blood T and B lymphocytes was done using rosette tests (E,EA,EAC) and the occurrence of surface immunoglobulins was determined by the immunofluorescent method with polyvalent anti-immunoglobulin serum. The counts of T and B lymphocytes in the peripheral blood were normal throughout the whole period of the observation, but from the 3rd week on a significant impairment of 3H-thymidine incorporation into the cells stimulated with Con A was observed, and from the 10th week on, this impairment appeared also in cells stimulated with PHA and PWM. These observations revealed considerable disturbances in cell-mediated reactivity in patients with ornithosis and seem to be connected with chronic infection with Chlamydia psittaci.     

A morphometric comparison of the nasopharyngeal airway of laboratory animals and humans

Solid silicone rubber casts of the nasopharyngeal and laryngeal regions of a human cadaver (child, 3 years old) and a laboratory primate (baboon, 10 years old) were made, and cross-sectional areas were measured in detail. Cross-sectional areas of other species reported in the published literature were used for comparison. In the child's nose cast, the frontal nasal duct (frontonasal duct), which enters the anterior part of the middle meatus, and the sphenoidal recess were almost absent. The ethmoidal turbinates (superior and middle concha) and the maxillary turbinates (inferior concha) were present but were not fully developed. In the baboon nose, the different turbinates were well defined and smooth but of a less complex nature than the child's nose. Of the species compared, the baboon's upper airways had the greatest similarity to the human child's. The present study shows that for the species investigated and for those from the literature, the cross-sectional area increases from the external nares to the maxilloturbinate region (inferior concha). There is a relatively sudden drop in cross-sectional area about halfway through the nose. The present study suggests a functional relationship between nasal structure and cross-sectional area across species.     

The dependence of twitch relaxation on sodium ions and on internal Ca2+ stores in voltage clamped frog atrial fibres

Frog heart relaxation was analyzed under voltage clamp conditions as the tension decay observed after the membrane potential had been returned to its resting value. The tension decayed exponentially with a time constant of 188±3.8 ms SEM. The relaxation rate decreased with the external Na concentration. It fell to about one tenth in a Na-free solution. Increasing the intracellular Na-content by an application of veratrine also decreased the relaxation rate. Thus relaxation seems dependent on the Na gradient. The relaxation rate decreased within one second upon switching from a high to a low Na-containing solution. The relaxation rate reached a minimum before rising slightly to a new steady state value. This rebound may reflect the partial recovery of the Na gradient since a fast variation in [Na]_i follows alteration of [Na]_o. Mn and La ions also slowed relaxation. In a Na-free solution, adrenaline accelerated tension decay, an effect not noticeable in frog heart contained in Ringer solution. Other cAMP-promoting agents, such as dibutyryl-cAMP and aminophylline, also increased relaxation rate.It is concluded that in frog myocardium, part of the decrease of the intracellular Ca²⁺-concentration which occurs during each cardiac cycle could be dependent on a Na–Ca exchange mechanism. The relative importance of this mechanism, versus internal Ca sequestration, in the relaxation of tension may well be greater in contractile tissues whose cells have a large surface/volume ratio.     

Organisation anatomique et physiologique des activités motrices de la moelle épinière

Résumé La moelle épinière utilise deux grandes modalités fonctionnelles: l'activité réflexe et l'activité programmée.L'activité réflexe constitute la modalité la plus anciennement connue, elle englobe de nombreux arcs réflexes imprégnés de finalités fort diverses. Ainsi le réflexe myotatique, arc monosynaptique le plus simple, maintient et protège le tonus musculaire; les réflexes à point de départ cutané, polysynaptiques, impliquant des réseaux interneuronaux, extériorisent des réponses motrices de défense et de protection indiquant déjà une compétence plus intégrative.L'activité programmée médullaire est supportée par des circuits neuronaux assez solidement fixés. Cette organisation fonctionnelle produit des séquences motrices correctement agencées dans l'espace et dans le temps (locomotion, miction, défécation, réflexes sexuels).Aces deux modalités basales viennent se superposer les influences supra-spinales à capacité exécutoire. Ces signaux, canalisés vers la voie finale commune, agissent, dans une faible part, directement sur les motoneurones spinaux et, en effet, dans une très large mesure, ils utilisent les circuits interneuronaux et modulent ou déclenchent réflexes et programmes médullaires engendrant ainsi une activité cinétique cohérente.     

Ultrastructural synaptology of Clarke's column

Summary An electron microscopic analysis of the synapses in Clarke's column of the cat, using fresh short term degeneration, long term degeneration for detection of the persisting elements, and a newly devised two-step degeneration technique using fresh short term degeneration for further analysis of the persisting synaptic elements in chronic degeneration cases. — Three kinds of synaptic terminals can be identified in the lower part (L₃ segmental level) of Clarke's column: (1) very large (so-called giant) axon terminals with spheric vesicles of primary muscle afferents establishing multiple (climbing-type) contacts mainly with the large dorsal spinocerebellar tract neurons; (2) small bouton-type terminals having spheric synaptic vesicles and originating mainly from spinal interneurons, localized below L₄ in the lumbar enlargement and contacting small distal dendrites and cell bodies of small cells; (3) two types of nerve terminals, originating from local neurons, and characterized by flattened vesicles. One type of (3) contacts mainly the large Clarke neurons directly, whereas the other establishes axo-axonic synapses with the giant terminals (1) of primary muscle affer ents. The possible functional significance of these findings is discussed.