Short-term effect of acupuncture on intraocular pressure in healthy subjects.

PURPOSE: To evaluate the short-term effect of acupuncture on the intraocular pressure (IOP) in healthy subjects. METHODS: A randomised controlled double-blinded trial was performed. 48 healthy volunteers (94 eyes) were randomly allocated to three groups: acupuncture group-19 subjects (38 eyes) were submitted to a 20 min session of acupuncture (GB1, GB14 and BL1); sham group-14 subjects (27 eyes) were submitted to a 20 min session of acupuncture with needles inserted in false points; and control group-15 subjects (29 eyes) who underwent no intervention. All subjects had the IOP measured by a masked investigator using Goldmann applanation tonometry immediately before intervention, as well as 20 min and 24 h after. RESULTS: The mean (SD) IOP in the acupuncture group was 17.9 (3.3) mm Hg at baseline, 16.4 (3.9) mm Hg at 20 min and 16.3 (3.3) mm Hg at 24 h. The mean (SD) IOP in the sham group was 18.6 (3.3) mm Hg at baseline, 17.7 (2.6) mm Hg at 20 min and 15.9 (3.6) mm Hg at 24 h. The mean (SD) IOP in the control group was 16.9 (3.5) mm Hg at baseline, 16.5 (3.8) mm Hg at 20 min and 15.8 (3.3) mm Hg at 24 h. There was no statistically significant difference in the IOP variation (post-intervention minus baseline measurements) between groups after 20 min (p=0.13) and 24 h (p=0.21). CONCLUSION: Acupuncture in the studied points did not produce significant short-term effect on the IOP of healthy individuals in comparison with control groups.

Electro-oculography of smooth pursuit and optokinetic nystagmus eye movements in type I Duane's retraction syndrome.

INTRODUCTION: These two eye movements have not been previously studied in this condition by this method. METHODS: Five cases were studied. Both visual acuity and eye examination of anterior and posterior segments were normal. A Nicolet Nystar Plus system with chloride silver electrodes was used to record the EOG. RESULTS: Of the two systems under study, the smooth pursuit system showed the most relevant anomalies, both in the Duane's eye and in the apparently healthy eye. No correlation was found between the pursuit and optokinetic nystagmus disorders. In some cases, more significant abnormalities were observed in the clinically normal eye. CONCLUSIONS: The results clearly demonstrated a significant impairment of the pursuit system. This suggests that this motor disorder is not exclusively caused by hypoplasia or aplasia of the nucleus of the abducens nerve (VIth cranial nerve). These abnormalities might be related to a poor development of the rhombencephalon since both supramotor nuclei as well as the pathways of this system arise from this region of the embryonic brain. In the particular case of OKN, the supramotor nuclei have a different origin. Therefore, these systems might be affected differently.

Predatory hunting and exposure to a live predator induce opposite patterns of Fos immunoreactivity in the PAG.

Considering the periaqueductal gray's (PAG) general roles in mediating motivational responses, in the present study, we compared the Fos expression pattern in the PAG induced by innate behaviors underlain by opposite motivational drivers, in rats, namely, insect predation and defensive behavior evoked by the confrontation with a live predator (a cat). Exposure to the predator was associated with a striking Fos expression in the PAG, where, at rostral levels, an intense Fos expression was found largely distributed in the dorsomedial and dorsolateral regions, whereas, at caudal levels, Fos-labeled cells tended to be mostly found in the lateral and ventrolateral columns, as well as in the dorsal raphe nucleus. Quite the opposite, insect predation was associated with increased Fos expression predominantly in the rostral two thirds of the lateral PAG, where the majority of the Fos-immunoreactive cells were found at the oculomotor nucleus levels. Remarkably, both exposure to the cat and insect predation upregulated Fos expression in the supraoculomotor region and the laterodorsal tegmental nucleus. Overall, the present results clearly suggest that the PAG activation pattern appears to reflect, at least partly, the animal's motivational status. It is well established that the PAG is critical for the expression of defensive responses, and, considering the present findings, it will be important to investigate how the PAG contributes to the expression of the predatory behavior, as well.

Peripheral ocular motor disorders.

In the reviewed period, articles on peripheral eye movement disorders covered interesting aspects. Localizing value of associated signs, repetitive presentations of palsies, and classical quotations are stressed for the oculomotor nerve. The superior oblique is correlated to central nervous system disorders when overacting in pediatric patients or when ocular torsion is matched to the perceived vertical tilt. The family "pseudo" brought two of its members: "pseudo" myasthenia and "pseudo" myotonia. Mitochondrial citopathies with ocular manifestations can overlap among the different clinical types, eg, Kearns-Sayre, MELAS (mitochondrial encephalopathy-lactic acidosis and strokelike episodes), MERFF (myoclonic epilepsy and ragged red fibers). The diagnostic value of DNA mutations is emphasized in those syndromes. Imaging of the carotid arteries provides useful hints in cases where the lumen is narrowed due to internal processes or external compression; its interpretation is not only of diagnostic but of prognostic value. Certain otorhinolaryngology surgical procedures can damage the orbital muscles and produce serious inconvenience to the ocular motility. Analyzing the involved structures the therapeutic gesture can be determined. Diplopia after cataract surgery or retinal detachment repair is due to different factors, anesthetics, or implant location and is implied in every case.

Effects of synaptic drugs on turtle optokinetic nystagmus and the spike responses of the basal optic nucleus.

Behavioral and electrophysiological measures were used to elucidate the retinal modulation of oculomotor control in the turtle. Eye movements were recorded following intravitreal applications of 2-amino-4-phosphonobutyrate (APB) and the GABA antagonists picrotoxin and bicuculline. Visual responses of single basal optic nucleus (BON) neurons of the accessory optic system were studied in parallel experiments. The effectiveness of APB, a glutamate analog thought to act selectively on the retinal ON pathway, was assessed independently by recording electroretinograms or ganglion cell activity. Injections of APB into the turtle's eye reduced or blocked the injected eye's ability to drive horizontal optokinetic nystagmus, as also observed in rabbit and cat (Knapp et al., 1988; Yucel et al., 1989). Single-unit recordings from the BON during APB superfusion (50-200 microM APB) of the contralateral retina demonstrated that these cells, which are direction-sensitive and respond to the offset of light flashes, have their responses to moving stimuli blocked by APB. During the APB effect, GABA antagonists were applied to the same eye. Although moderate doses of APB were sufficient to block optokinetic or BON light responses, the addition of GABA blockers still elicited a spontaneous temporal-to-nasal nystagmus (Ariel, 1989) or visually responsive yet direction-insensitive responses from BON cells (Schuerger et al., 1990). These results are discussed in terms of the retinal output to pathways involved in oculomotor control of optokinetic nystagmus.

Thalamic origin of neuropeptide Y innervation of the accessory optic nucleus of the pigeon (Columba livia).

Immunohistochemical and tracing techniques were used in combination to reveal the source of a neuropeptide Y-like immunoreactive (NPY-LI) plexus in the nucleus of the basal optic root (nBOR) of the pigeon accessory optic system. Injections of rhodamine-labeled latex microspheres into nBOR produced retrograde labeling of a population of neurons interposed between the principal optic nucleus of the dorsolateral thalamus (equivalent to the mammalian dorsal lateral geniculate nucleus) and the ventral lateral geniculate nucleus. The retrogradely labeled neurons were distributed mainly in the immediate vicinity of the lateral, dorsal, and ventral aspects of the nucleus rotundus. Immunohistochemical methods revealed many NPY-containing somata within the same intergeniculate thalamic area. Double-labeling immunohistochemical and retrograde tracing experiments evidenced that many NPY-LI neurons in the intergeniculate area contained rhodamine microspheres that had been previously injected into the ipsilateral nBOR. The projection of that general thalamic area to the nBOR was then confirmed by means of anterograde transport of Phaseolus vulgaris leucoagglutinin. In these experiments, the intergeniculate region was demonstrated to project to all divisions of the nBOR and to every other retino-recipient structure, including the suprachiasmatic nucleus. Finally, electrolytic lesions of the intergeniculate area produced a dramatic reduction in the number of NPY-LI axons and terminals within the ipsilateral nBOR and also within other retino-recipient structures. These data indicate the existence of a thalamic NPY-LI projection to the pigeon nBOR of the accessory optic system. This chemically specific projection originates from the intergeniculate area, which was shown in this study to project to all other retino-recipient structures. Thus, NPY may have a role in the functional organization of the accessory optic system and also of the avian visual system as a whole.