María José Mosquera González

Afferent and efferent connections of the torus semicircularis in the sea lamprey: an experimental study

The afferent and efferent connections of the torus semicircularis (TS) of larval sea lampreys were studied with horseradish peroxidase, carbocyanine dye (DiI) and fluorescein-coupled or Texas-Red-coupled dextran amine tract-tracing methods. Application of tracers to the TS or to the octavolateral area revealed the presence of bilateral projections from the octavolateral area to the torus semicircularis, mainly from the mechanoreceptive regions (medial and ventral octavolateral nuclei) though also from the electroreceptive (dorsal octavolateral nucleus) region. The nucleus of the descending root of the trigeminal nerve projects to the contralateral TS, mostly from neurons located rostral to the obex. Fairly numerous reticular cells of the rhombencephalon project to the torus semicircularis. In the mesencephalon, scattered cells in the tegmentum, and some in the tectum, have toral projections, mostly ipsilateral. Numerous thalamic neurons, as well as fairly numerous neurons of the posterior tubercle, hypothalamus and preoptic region, and a few neurons in the ventral telencephalon (striatum, septum), were labeled after tracer application to the TS. The torus semicircularis mainly projects to the thalamus, the hypothalamus and the reticular rhombencephalic nuclei. Our results reveal for the first time a complex pattern of connections of the lamprey TS, which suggests that it is a multisensory center integrating head cutaneous sensitivity with mechano- and electrosensory information from the octavolateral area and with visual information. A number of afferents from the forebrain also appear to contribute to TS function.

OCTAVOLATERAL NEURONS PROJECTING TO THE MIDDLE AND POSTERIOR RHOMBENCEPHALIC RETICULAR NUCLEI OF LARVAL LAMPREY : A RETROGRADE HORSERADISH PEROXIDASE LABELING STUDY

The octavolateral area of lampreys, which receives primary fibers from the octaval and lateral line nerves, is involved in the premotor organization of body movements through secondary projections to the reticular formation. Here, the typology of neurons of the three octavolateral nuclei (ventral, medial, and dorsal) that putatively project to the middle and posterior rhombencephalic reticular nuclei were studied by retrograde transport of horseradish peroxidase (HRP) applied to these reticular nuclei. Several types of neurons were labeled in the ventral nucleus, both ipsilateral and contralateral to the site of HRP application. Some of these neurons showed a rather simple morphology (octavomotor neurons, monopolar cells), but most had more‐ or less‐branched dendrites that were associated with one, or several, fields of terminal fibers in the octavolateral area. Unlike those of the ventral nucleus, labeled neurons of the medial nucleus were homogeneous in appearance (mostly pear‐shaped). The dorsal nucleus was scarcely developed in larvae, as judged from the very simple and small labeled cells. The presence of terminal or “en‐passant” boutons of secondary octavolateral fibers in the reticular area and the commissural nature of these fibers were also investigated by means of application of HRP or indocarbocyanine dye to the octavolateral nuclei. In addition, neurons of other alar plate nuclei that were labeled by the HRP application to the reticular nuclei (trigeminal descending root nucleus and solitary nucleus) were also characterized. The functional significance of these results is discussed. J. Comp. Neurol. 384:396–408, 1997.

Distribution of thyrotropin-releasing hormone immunoreactivity in the brain of larval and adult sea lampreys, Petromyzon marinus L.

This study investigated the distribution of thyrotropin‐releasing hormone‐immunoreactive (TRHir) neurons and fibers in the brain and retina of lampreys. Our results in the brains of large larvae and upstream‐migrating adults of the sea lamprey showed the presence of TRHir neurons mainly in the preoptic region and the hypothalamus. A few TRHir neurons were also found in the striatum. The number and staining intensity of TRHir neurons increased from larval stages to adulthood, and the distribution of TRHir populations was wider in adults. The TRHir fibers were more easily traced in adults. Some TRHir fibers entered the neurohypophysis, although most fibers coursed in the different regions of the brain, mostly in the basal region, from the forebrain to the hindbrain. The presence of TRHir stellate cells was observed in the adenohypophysis. In the retina of adult lampreys, but not in that of larvae, TRHir amacrine cells are present. J. Comp. Neurol. 453:323–335, 2002.

GABA-immunoreactive internuclear neurons in the ocular motor system of lampreys

The presence of internuclear neurons in the abducens and oculomotor nuclei of lampreys [González, M.J., Pombal, M.A., Rodicio, M.C. and Anadón, R., Internuclear neurons of the ocular motor system of the larval sea lamprey, J. Comp. Neurol. 401 (1998) 1-15] indicates that coordination of eye movements by internuclear neurons appeared early during the evolution of vertebrates. In order to investigate the possible involvement of inhibitory neurotransmitters in internuclear circuits, the distribution of gamma-aminobutyric acid (GABA) in the extraocular motor nuclei of the lamprey was studied using immunocytochemical techniques. Small GABA-immunoreactive (GABAir) neurons were observed in the three ocular motor nuclei. Numerous GABAir neurons were observed in the group of internuclear neurons of the dorsal rectus oculomotor subnucleus. A second group of GABAir neurons was observed among and below the trochlear motoneurons. Two further groups of GABAir interneurons, periventricular and lateral, were located in the abducens nucleus among the cells of the caudal rectus and the ventral rectus motor subnuclei, respectively. In addition to the presence of GABAir neurons, in all the ocular motor nuclei the motoneurons were contacted by numerous GABAir boutons. Taken together, these results suggest that GABA is involved as a neurotransmitter in internuclear pathways of the ocular motor system of lampreys.

INTERNUCLEAR NEURONS OF THE OCULAR MOTOR SYSTEM OF THE LARVAL SEA LAMPREY

The internuclear neurons of the ocular motor system of lampreys are characterized here for the first time. Horseradish peroxidase (HRP), fluorescein‐, or Texas red– (TRDA) coupled dextran‐amine applied into the oculomotor nucleus of larval lamprey (Petromyzon marinus) retrogradely labeled two populations of contralateral abducens interneurons, one lateral and the other periventricular. Tracer application to the abducens nucleus anterogradely labeled thick contralateral fibers that specifically contact the medial rectus motor subnucleus by means of large boutons. Local application of TRDA to this subnucleus allowed identification of the lateral abducens interneurons as the origin of this projection. Electron microscopy of the medial rectus motor subnucleus showed large boutons bearing round synaptic vesicles that contact on the perikarya, as well as small boutons with pleomorphic vesicles. This lateral rectus (abducens) – medial rectus (oculomotor) internuclear projection of lampreys appears to be similar to those involved in the coordination of horizontal eye movements in mammals. The periventricular abducens interneurons projected bilaterally to other oculomotor subnuclei. Tracer application to the abducens nucleus labeled a group of small interneurons in the ipsilateral dorsal rectus motor subnucleus. Anterograde labeling indicates that oculomotor interneurons project ipsilaterally to the ventral rectus abducens subnucleus, thus, corresponding to oculomotor interneurons found in mammals and frogs. The interneurons of the dorsal rectus and ventral rectus motor subnuclei are probably involved in the control of conjugate vertical eye movements. The present results strongly suggest that the internuclear coordination of conjugate eye movements appeared in the earliest vertebrates. The homologies of extraocular muscles of lampreys and gnathostomes were reexamined. J. Comp. Neurol. 401:1–15, 1998.

Acupuncture for soft tissue shoulder disorders: a series of 201 cases

A retrospective observational study was performed on shoulder pain cases seen in a community general practice. Two hundred and one patients were treated with acupuncture (on distant points plus local shoulder points), moxibustion and auriculotherapy. Data was retrieved from records over a three-year period to assess the effect of acupuncture and moxibustion on pain, mobility and disability, and to compare perceived efficacy rates with published reports from Chinese acupuncturists. Using a four-point outcome scale in this series of 201 patients the study found: one patient (0.5%) reported no improvement, 12 (6%) simple improvement, 68 (33.8%) remarkable improvement, and 120 (59.7%) clinical resolution. Only two patients left the programme. In conclusion, treatment of soft tissue shoulder disorders with acupuncture and moxibustion in this series seems to have good clinical results in diminishing symptoms, shortening disease duration time and improving functional ability, even in long-lasting disease (up to 10 years). A combination of distant points plus local points, moxibustion and auriculotherapy seems to increase effectiveness, reduce the number of sessions per patient, and increase the time between sessions, suiting the needs of patients and those of a busy National Health Service clinic. The authors report results similar to those reported by Chinese acupuncturists when using similar diagnostic procedures, techniques, outcome measures and patients. This case series is the first step towards conducting a randomised controlled trial (RCT) of acupuncture efficacy in shoulder pain. Such trials are needed to confirm the perceived efficacy of acupuncture from observational studies.