José Enrique García-Mauriño

Immunohistochemical localization of nerve growth factor in the rat pineal gland

Sympathetic nerve fibers arising from the superior cervical ganglia are the main innervation of the rat pineal gland. Since most organs innervated by these ganglia contain nerve growth factor (NGF), the hypothetical existence of NGF in the pineal gland was investigated. The peroxidase anti-peroxidase technique was applied for the immunohistochemical demonstration of NGF using a polyclonal antiserum on Bouin-fixed, paraffin-embedded pineal glands from adult, young and 6-hydroxydopamine (6-OHDA)-treated rats. Few immunopositive cells were observed in the adult pineal gland. A more conspicuous population of immunoreactive cells was noted in young animals (20-45 days old), especially in those chemically denervated with 6-OHDA. NGF immunoreactive cells displayed a stellate shape resembling the interstitial or glial cells previously described in the rat pineal gland. Since NGF plays a trophic effect on sympathetic neurons during development and adulthood, we postulate that its presence in the pineal gland may exert a trophic role on its sympathetic innervation.

Presence of Melanin in the Cat Pineal Gland

Light- and electron-microscopic features of pigmented cells in the cat pineal gland are described. These cells were observed throughout postnatal life from the second postnatal day to the oldest cats studied (up to 13 years old). No apparent relationship was observed among the amount of pigment and the animal age or sex. Pigmented cells showed a preferential localization at the ventral surface of the pineal gland near its distal end. The pineal pigment was histochemically identified as melanin. Pineal pigment granules showed ultrastructural features similar to melanocyte melanin granules.

Postnatal Development of the Dog Pineal Gland: Electron Microscopy

The ultrastructure of the dog pineal gland from the first postnatal day to the seventh month is described. In the first postnatal stages, pineal parenchyma only shows immature proliferative cells with abundant cytoplasmic glycogen. Nerve fibers are seen in the pineal connective tissue spaces. The differentiation of the dog pineal cell types begins in the first postnatal week. Both pinealocytes and pigmented cells are first seen on the fourth postnatal day. The pineal astrocytes are observed on the tenth day. Immature cells are still found in the pineal gland of 1 mo‐old dogs. The differentiation of the dog pineal cell types is completed by the second postnatal month.

Immunocytochemical localization of basic fibroblast growth factor in the rat pineal gland

Marín F, Boya J, Calvo JL, López‐Muñoz F, García‐Mauriño JE. Immunocytochemical localization of basic fibroblast growth factor in the rat pineal gland. J. Pineal Res. 1994: 16: 44–49.

Postnatal Development of the Rabbit Pineal Gland

The development of the rabbit pineal gland has been studied by light and electron microscopy from the 1st to the 120th postnatal day. After 24 h of postnatal life, the pineal parenchyma is highly cellular, showing two identifiable cell types: pinealocytes I and II. Immature type II pinealocytes arrange either in cellular cords or clusters or forme rosette-like structures. At the 5th postnatal day, corticomedullar differentiation is established. Rosette-like structures and cellular cords are absent from the cortex. Along the postnatal period, nuclei of pinealocytes are set apart due to cytoplasmic widening and development of cell processes. These structures pervade the cellular cords and rosette-like structures formed by immature type II pinealocytes. Rosette-like structures are no longer seen beyond the 30th postnatal day, and cords of type II pinealocytes from the 90th postnatal day on. At this time, the rabbit pineal gland is considered to be histologically mature.

Effects of dietary 2,2', 4,4'-tetrabromodiphenyl ether (BDE-47) exposure in growing medaka fish (Oryzias latipes).

In this research work, we addressed the effects of a diet fortified with BDE-47 (0, 10, 100, 1000ng/g) dosed to 4-7 day-old post-hatch medaka fish for 40 days, followed by an 80-day depuration period. BDE-47 accumulation and overall growth were evaluated throughout the dosing period, and its elimination was quantified over the following 60 days. The histological condition of the thyroid gland, liver and gonads from the 1000ng BDE-47-treated fish were assessed 5 and 70days after exposures finished. The phenotypic males to females ratio was also quantified 70days after treatments finished. Sixty days after the BDE-47 exposures, reproductive capacity (i.e. fecundity, fertility and hatchability) was evaluated in mating groups for a 20-day period. BDE-47 exposure via food from larval through juvenile life stages of medaka fish resulted in steady accumulation with time dose-dependently. This accumulation tendency rapidly decreased after dosing ended. The growth rates showed a significant increase only at the highest concentration 70days after exposures finished. The histological survey did not reveal BDE-47-related alterations in the condition of the potential target organs. However, a morphometrical approach suggested BDE-47-related differences in the thickness of the epithelium that lines thyroid follicles. The reproduction studies showed comparable values for the fecundity, fertility and hatching rates. Dietary BDE-47 dosed for 40days to growing medaka fish did not alter the phenotypic sex ratios at maturity. The dietary approach used herein could not provide conclusive evidence of effects on medaka development and thriving despite the fact that BDE-47 underwent rapid accumulation in whole fish during the 40-day treatment.

Influence of the light and dark phase of the cycle on the cellular proliferation in the pineal gland of the adult rat : A bromodeoxyuridine immunohistochemical study

ABSTRACT: The cellular proliferative activity in the adult rat pineal gland was studied using bromodeoxyuridine immunohistochemistry during the light and dark phases of an artificial 12L: 12D photoperiod. The results showed statistically significant differences in the number of labeled cells between the light and dark phases, with the labeled cells being almost threefold more abundant in the light period. Minor changes were also found in the pineal gland volume between both periods. The decrease in the number of labeled cells in the dark phase of the cycle could be related to the well‐documented antimitotic action of melatonin.

Bioaccumulation, maternal transfer and effects of dietary 2,2′,4,4′-tetrabromodiphenyl ether (BDE-47) exposure on medaka fish (Oryzias latipes) offspring

A previous study conducted in our laboratory with growing medaka (Oryzias latipes) showed the capacity of BDE-47 (10-1000ng/g) to bioaccumulate during a 40-day oral exposure. However, the results did not provide evidence for effects during or after the exposure period. In this study, breeding medakas were fed a diet for 40days that contained 1000ng of BDE-47/g. At predefined time points, females (time points 10, 20, 30 and 40), males (time points 30 and 40) and pools of laid eggs (time points 10, 20, 30 and 40) were sampled and collected for: 1) the BDE-47 quantitative analysis in adults in the <24-h-old post-fertilization (hpf) embryos, and in the <24-h-old post-hatch (hph) eleutheroembryos; 2) the evaluation of fecundity, fertility and hatching. Additional pools of embryos collected at time point 40 were evaluated for: 1) the active swimming behavior of the 48hph offspring in the eleutheroembryonic stage; 2) the BDE-47 quantification in the 240hph resultant larvae. BDE-47 accumulated in parents rapidly, and concentrations remained constant at higher levels in males (values within the 50-60ng/g wet weight -w.w.- range) compared with females (70ng/g w.w. range). The BDE-47 concentrations detected in embryos and eleutheroembryos ranged from 200 to 500ng/g w.w. for time points 10-40. Reproductive capacity, hatching and ensuing swim bladder inflation were not affected by parental BDE-47 dietary exposure, nor was the active swimming behavior in eleutheroembryos. The BDE-47 concentration in the 240hph larvae lowered to levels close to those detected in parents. Despite the efficient BDE-47 maternal transfer, these results offered no evidence for BDE-47 effects on fish reproduction or in the early life stages of offspring.

Astrocytic Reaction After Traumatic Brain Injury

Astrocytes and microglia respond to a great variety of lesions in the nervous tissue of the central nervous system (CNS). In this sense, although astroglial cells react in a relatively constant manner, the intensity and time course of the changes are largely dependent upon the type of lesion involved.