Herminia Perez-Gonzalez

Sources of GABAergic input to the inferior colliculus of the rat

We have studied the GABAergic projections to the inferior colliculus (IC) of the rat by combining the retrograde transport of horseradish peroxidase (HRP) and immunohistochemistry for γ‐amino butyric acid (GABA). Medium‐sized (0.06–0.14 μl) HRP injections were made in the ventral part of the central nucleus (CNIC), in the dorsal part of the CNIC, in the dorsal cortex (DCIC), and in the external cortex (ECIC) of the IC. Single HRP‐labeled and double (HRP‐GABA)‐labeled neurons were systematically counted in all brainstem auditory nuclei.

Postnatal development of NADPH-diaphorase activity in the superior colliculus and the ventral lateral geniculate nucleus of the rat ☆

We have studied the postnatal development of dihydronicotinamide adenine dinucleotide phosphate diaphorase (NADPH-d) activity in the superior colliculus (SC) and the ventral lateral geniculate nucleus (LGv) of the rat. We describe two different developmental patterns of NADPH-diaphorase activity. The first pattern, observed in the deep layers of the SC, shows a transient activity during the first week which progressively decreases during the following two weeks. The second pattern is observed in the superficial layers of the SC and in the LGv. They become positive during the first week, their NADPH-d activity increases progressively during the second and third weeks, reaching the adult pattern at the fourth week. On the whole, the developmental chronology of the laminar distribution of NADPH-d in the SC displays an inside-out pattern. Our results suggest that NADPH-d activity may play different roles at different stages of the developing nervous system.

Changes in the secretory activity of the subcommissural organ of spontaneously hypertensive rats

The subcommissural organ (SCO) is a glandular circumventricular organ secreting glycoproteins into the cerebrospinal fluid. The SCO of 15-week-old spontaneously hypertensive rats (SHR) and of matched normotensive Wistar-Kyoto rats (WKY) was studied immunocytochemically by using an antibody against the glycoproteins secreted by the SCO. The blood pressure, water intake and volume of brain ventricles of SHR and WKY rats were also recorded. The SHR were hypertensive, drank more water and did not display dilatation of the brain ventricles. The SCO of the SHR rats showed a drastic decrease of the immunoreactive material stored in the rough endoplasmic reticulum whereas the amount of immunoreactive apical secretory granules did not vary with respect to the SCO of WKY rats. These changes are compatible with an increased secretory activity of the SCO of the SHR rats. It is suggested that the changes in the SCO of SHR rats, and their hypertensive state, are interrelated phenomena.

Alcohol Intake Effects on the Dorsal Vagal Complex of the Rat: A Cellular Morphometric Study

We have analyzed the morphometric effects on the dorsal vagal complex (DVC) of the rat of alcohol exposure and/or hypoproteic diet intake during 8 weeks. In the area postrema (AP), alcohol treatment (combined with normal isoproteic or hypoproteic diet) caused a significant decrease in karyometric parameters. In the dorsal motor nucleus of the vagus (DMV) and nucleus tractus solitari (NTS), the alcohol isoproteic intake (AI) produced an increase in neuron size (expressed by an increase in the neuronal nuclear area and the cell/neuropil coefficient). The hypoproteic diets produced a reduction in the global volume of each structure of the DVC which was accompanied by a decrease in global brain volume. These results indicate that after 8 weeks of treatment, alcohol is the main cause of the morphometric alteration found in the DVC, while variations in the amount of protein intake appear to produce global effects on the whole brain.

The effects of chronic administration of captopril on the mouse subfornical organ and area postrema

We have studied by morphometric procedures the chronic effect of captopril on the subfornical organ (SFO) and area postrema (AP) of the adult mouse. Oral administration of captopril does not produce any change in the size of individual nuclei of the ependymocytes and neurons in both centers. However, there are other quantitative effects of captopril on the global volume of the SFO and on the neuropil and vascular elements of both the SFO and AP which present a significant increase. It is suggested that this increase is due to metabolic processes at the level of both circumventricular organs.

Alcohol effects on the morphometric development of the subfornical organ and area postrema of the albino mouse

We have studied the development of the nuclear sizes of ependymocytes and neurons of two circumventricular organs of the male alcoholic mouse: the Subfornical Organ (SFO) and the Area Postrema (AP), comparing the results with a control group. The global volume of both centers was also studied. The results show that the SFO, a structure related to the control of fluid balance, responds to alcoholism with an increase of the global volume. This increase could be related to the variations of salt-water balance and/or blood pressure in chronic alcoholism. However, the size of cell nuclei in the SFO is not affected. In contrast, the AP responds to chronic alcoholism like other nervous centres, with a decrease of the nuclear size of its cells. The global volume of AP does not change.

Protein changes in the cerebrospinal fluid of the different types of perinatal human hydrocephalus

Background Hydrocephalus is a disorder characterized by brain ventricular dilation and excess of cerebrospinal fluid (CSF), in many cases its etiopathic origin is acquired as: post-hemorrhage, meningitis and tumours. But, there is no attributable cause in 45% of hydrocephalus cases and foetal hydrocephalus due to aqueductal stenosis is one of the two main groups of non acquired or congenital hydrocephalus, however whether narrowing of the aqueduct of Sylvius is cause or consequence of hydrocephalus is discussed by different authors. Anyhow, most investigators describe an alteration in the SCO and certain circumventricular structures in the hydrocephalus, that can even occur before hydrocephalus is present and of course before the aqueduct stenosis. The objective of the present work is to investigate probable changes in the protean composition of the CSF in perinatal hydrocephalus and to analyze, in those liquids, the presence of soluble proteins that are immunoreactive or antibodies against Reissner fibre proteins and human foetal SCO extracts

Alcohol Effects on Paraventricular Hypothalamic Nucleus Morphometry

The morphometric effects of postnatal exposure to alcohol on the neurons of the paraventricular hypothalamic nucleus (PVN) have been studied in four different topographic subdivisions of the nucleus: rostral, intermediate medial, intermediate lateral and caudal. Male mice were exposed to alcohol during lactation and after weaning by addition of 20% of ethanol to the drinking water that was first ingested by the mother and thereafter by the experimental animals themselves. Animals were sacrificed at the 25th, 35th, 45th, 55th and 100th postnatal day. Nuclear sizes of the PVN neurons (Perimeter, area and maximum diameter) were determined in both control and experimental alcohol-treated groups. The shape of these neuronal nuclei was also determined and compared. PVN responds globally to alcohol exposure, showing a decrease in the neuronal nuclear sizes in the four studied PVN subdivisions of the alcohol-treated mice at the 35th and 45th and 100th day. We suggest that these decreases could be related to changes in gonadal hormone levels induced by alcohol exposure and/or disturbances of brain neurotransmitter and neuropeptide metabolism caused by ethanol.

Expression of certain cerebrospinal fluid proteins in hydrocephalus and aging. A study on WKY rats

Spina Bifida Meeting abstracts - A single PDF containing all abstracts in this supplement is available here .