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J M Palomares

Publications and source records attributed to J M Palomares.

5 recordsLinked to original sources
PubMed2000

[Evidence for glutamatergic neurotransmission in the geniculo-cortical pathway in the rat].

PURPOSE: To investigate the possible participation of glutamate in the neurotransmission of the rat geniculo-cortical pathway. METHODS: In a first set of experiments, we studied the effects of microiontophoresis of kynurenate, a broad spectrum antagonist of glutamate receptors, on the excitation evoked in visual cortex cells by electrical stimulation of the dorsal lateral geniculate nucleus and the optic tract. Cell activity was determined by extracellular unit recordings. In a second set of experiments, we studied the effects of electrical stimulation of the dorsal lateral geniculate nucleus and the optic tract on the release of glutamate and aspartate in the visual cortex in vivo. Push pull perfusions were made in the visual cortex and the amino acids contents of the perfusates were analysed by high performance liquid chromatography. RESULTS: Microiontophoresis of kynureate in area 17 cells selectively supressed the excitatory response to dorsal geniculate nucleus and optic tract stimulation. On the other hand, stimulation of these structures significantly increased glutamate, but not aspartate, release in area 17. CONCLUSIONS: These results demonstrate that glutamate is the neurotransmitter of the geniculo-cortical pathway in the rat.

Animals↗
PubMed1998

Electrophysiological and neurochemical study of the rat geniculo-cortical pathway. Evidence for glutamatergic neurotransmission.

The projection from the dorsal lateral geniculate nucleus to the primary visual cortex of the rat was studied electrophysiologically. Electrical stimulation of the dorsal lateral geniculate nucleus and the optic tract produced three types of responses on neurons of area 17: excitation followed by inhibition, excitation and inhibition. These results extend and confirm, in adult rats, previous studies done in rat geniculate-visual cortex cocultures preparations in vitro. The role of glutamate in the neurotransmission of the rat geniculo-cortical pathway was also investigated. In a first set of experiments, the effects of kynurenate, an antagonist of glutamate receptors, on visual cortex neurons with a monosynaptic excitatory response to dorsal lateral geniculate nucleus stimulation were studied. Microiontophoresis of kynurenate in area 17 neurons selectively suppressed the excitatory response to dorsal lateral geniculate nucleus and optic tract stimulation. In a second set of experiments, the effects of electrical stimulation of the dorsal lateral geniculate nucleus and the optic tract on the release of amino acids in the rat visual cortex in vivo were studied. Using the push-pull method, we perfused a discrete region of the visual cortex with artificial cerebrospinal fluid (CSF), and the amino acid content of the perfusates was analysed by high performance liquid chromatography (HPLC). Stimulation of either the dorsal lateral geniculate nucleus or the optic tract significantly increased glutamate release in area 17. The rest of the amino acids studied did not show significant changes. The results provide evidence for the participation of glutamate in the neurotransmission of the geniculo-cortical pathway in the rat.

Animals↗
PubMedDate not supplied

Atypical thyroiditis in Huelva, Spain.

OBJECTIVE: To report an epidemic of atypical thyroiditis that occurred in southwestern Europe during 1995. METHODS: We present the clinical, laboratory, morphologic, and histologic features of 672 cases of thyroiditis and describe the results of treatment. RESULTS: During 1995, atypical thyroiditis was diagnosed in 672 of 725 patients with thyroid disorders encountered at our medical center in Huelva, Spain. Of these patients, 98% were women with normal ovarian function. The clinical findings were acute or subacute manifestation of diffuse nodular enlargement of the thyroid and spontaneous, severe pain on deglutition and palpation of the gland. Initial hematology and serum biochemistry studies, free triiodothyronine, free thyroxine, thyrotropin, and thyroid-stimulating immunoglobulins were in the normal range, but after the second week, the thyrotropin level began to increase. Thyroid antibodies (thyroglobulin and thyroid peroxidase) increased up to 300 times the high-normal level. Ultrasonography exhibited diffuse nodular enlargement of the thyroid gland, with irregular hypoechoic, normal, and hyperechoic zones. Fine-needle aspiration biopsy showed abundant lymphocytic infiltration. The best treatment results were obtained with the combination of levothyroxine and deflazacort. Because the epidemic appeared after a severe drought of 5-year duration (1991 to 1995) and affected women with normal ovarian function, our etiopathogenetic hypothesis was that an estrogen-like chemical substance polluted the area swamps. The high concentration of the pollutant was attributable to diminished water levels (8% of their capacity at the end of the drought period), and this situation may have affected the population through tap water used for human consumption. CONCLUSION: We describe an atypical autoimmune thyroiditis that affected primarily women of reproductive age, after a severe drought. The main features were a very painful, diffuse nodular enlargement of the thyroid gland, substantially increased thyroid antibodies, good response to levothyroxine and deflazacort combination treatment, and a benign evolution to chronic thyroiditis. Pollutants from various sources should be considered when atypical thyroiditis occurs in any community.

Journal Article↗