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F Pellicer

Publications and source records attributed to F Pellicer.

10 recordsLinked to original sources
PubMed1991

Naloxone effects on the visual evoked potentials recorded from the main and accessory visual pathways of the cat.

1. The effects produced by repetitive i.v. administration of naloxone (1, 2 or 4 mg/kg) on the visual evoked potentials (VEPs) recorded along the main and accessory visual pathways were investigated in a modified "encéphale isolé" cat preparation. 2. Naloxone provoked a progressive amplitude enhancement and latency reduction of some components, depending on the structure analyzed, the dose used and the number of administrations applied. Electroretinogram (ERG) and N1-P1 VEP components of optic chiasm (OCh), lateral geniculate body (LGB) and visual cortex (VC) did not present significant changes. 3. Late-latency components (more than 200 msec) appeared in the VEPs of LGB and VC, mainly when 4 mg/kg were used. 4. Our results suggest that endogenous opioids have a modulatory role in the processing of sensory information at different levels of the visual system.

Animals↗
PubMed1988

Naloxone facilitates sensory precipitation of focal and generalized seizures: evoked potentials and power spectral analysis in the cat.

To analyze the role of endogenous opioids on epileptogenesis the effect of repeated doses of naloxone alone (NA) (2, 4, and 8 mg/kg every 15 min) or along with intermittent photic stimulation (NPS) (1, 3, and 10 Hz) was tested on acute "Encephale isolé" cats. The electrical activity recordings of sensorimotor cortex (SMC), visual cortex, and right and left amygdalae revealed progressive changes as naloxone was administered: (A) slow spindle activity (4-6 Hz) in SMC, (B) 12 Hz rhythmic activity in both amygdalae, (C) generalized paroxysms, and (D) spontaneous tonic-clonic electrographic seizures. These changes occurred in both experimental groups (NA, NPS), and their onset was dose-related. Photic stimulation precipitated these phenomena. The amplitude of the visual evoked potential components (N1-P1, P1-N2, N2-P2) and power spectral analysis of spontaneous and evoked activity underwent progressive changes. Our results confirm a facilitatory effect of naloxone on epileptogenesis and suggest a possible role of endogenous opioids in this process and on sensory pathways' excitability.

Amygdala↗
PubMedDate not supplied

Habituation and dehabituation of the spinal polysynaptic reflex responses: modification by naloxone and opiates and their anatomical correlates.

The sustained inhibitory action of spinal endorphins could be responsible for the habituation of polysynaptic responses in the spinal cord. To test this hypothesis, acute spinalized unanesthetized cats (decerebrated and curarized) were used. Sural nerve electrical stimulation (0.2 Hz) was provided and a progressive decrease in the reflex response was found. Conversely, the field potential (lamina V) progressively increased during stimulation, reaching its maximum amplitude when ventral root response showed maximum habituation. The administration of naloxone (0.8-10.0 mg/kg) produced dehabituation or prevented habituation. The immunohistological results showed leu-enkephalin-like immunoreactive dot-like structures in close proximity to neurons of laminae VII, VIII and IX in the lumbo-sacral segment of the spinal cord. Our results suggest an involvement of opioid peptides in the habituation process.

Animals↗
PubMedDate not supplied

Massed amygdaloid kindling in encéphale isolé cats: its facilitation by naloxone.

The effect of repetitive administration of naloxone on the development of massed amygdaloid kindling in 'encéphale isolé' cats was studied. Electrical amygdaloid kindling was carried out with a 15 min inter-stimulus interval (ISI) in a control situation with intravenous (i.v.) naloxone administration (2, 4, and 8 mg/kg), 5 min prior to amygdaloid stimulation. It was found that it was possible to complete the amygdaloid kindling process in the encéphale isolé preparation reaching generalized electrographic tonic-clonic self-sustained seizures. The enhancement of the duration, frequency, and propagation of the after-discharge (AD) was accentuated by naloxone which also induced a progressive amplitude increment of the first potential evoked by the onset of the tetanus. The number of trials needed to achieve seizure generalization was reduced in dose-dependent manner by naloxone. The ability of naloxone to accelerate the development of amygdaloid kindling may be related to an inhibitory role of opioid peptides in this process.

Amygdala↗
PubMedDate not supplied

Epileptogenesis and muscular hypertonic postictal phenomena induced by naloxone in intact cats.

Epileptogenesis produced by repeated i.p. administration of naloxone chloride and sensory stimulation (photoacoustic stimulation at 1, 3, 10, and 15 Hz) every 15 min was studied in freely moving cats. The repeated administration of naloxone provoked some behavioral manifestations that resemble those produced by electrical amygdaloid kindling. Photoacoustic stimulation accentuated the manifestations. All the animals presented generalized behavioral seizures when total naloxone administration reached 80 mg/kg. None of the animals demonstrated postictal depression. These results suggest an inhibitory role of endogenous opioids and/or GABA in epileptogenesis.

Acoustic Stimulation↗
PubMedDate not supplied

[Jugular phlebectasia. Apropos a case].

We present a case of 6-years-old male with an internal jugular phlebectasia, diagnosed at our Hospital. Review of the bibliography, and complementary examination, like doppler, echography and digital intravenous angiography subtraction (DIVAS) was made.

Angiography, Digital Subtraction↗