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Biomedical subjects

F Alba

Publications and source records attributed to F Alba.

At least 73 records · Page 4Linked to original sources
PubMed1986

Asymmetrical distribution of aminopeptidase activity in the cortex of rat brain.

The levels of soluble aminopeptidase (AP) activity were measured in the right and left frontal (FC), parietotemporal (PTC) and occipital (OC) cortex of male albino rat brains. The results showed more AP activity in the left cortex than in the right. Analyzing these results further, we found that the differences are significant for frontal cortex but not for parietotemporal nor occipital cortex. However, 76% of the rats were left-predominant for AP activity in the 3 cortical areas studied.

Aminopeptidases↗
PubMed1983

Monoamines and self-stimulation of the medial prefrontal cortex in the rat.

The participation of noradrenaline (NE) and serotonine (5-HT) in self-stimulation (SS) of the medial prefrontal cortex (MPC) in the rat has been studied. Three groups of rats with bilateral electrodes implanted into the MPC were used in these experiments. In one of the groups, electrodes were also implanted into the locus coeruleus. In the first group, the rats received systemic injections of the following drugs: clonidine (alpha-agonist), phenoxybenzamine (alpha-antagonist), isoproterenol (beta-agonist) and propranolol (beta-antagonist). In the second group, p-chlorophenylalanine (a 5-HT synthesis inhibitor) was administered intragastrically and SS measured during the following 16 days. In these two groups of rats and previous to every SS session, spontaneous motor activity (SM) was measured as control for non specific effects of the drugs. In a third group of rats, lesions of the locus coeruleus were performed unilaterally and SS measured in both prefrontal cortex during the following 16 days post-lesion. SS contralateral to the lesioned side served as control for non-specific effects of the lesions. After all these treatments, SS of the MPC was not specifically affected. Our results suggest the non participation of NE and 5-HT terminals in the neural substrates underlying SS of the MPC.

Adrenergic alpha-Antagonists↗
PubMed1982

[Not Available].

Explore the source record for details and available documents.

Demography↗
PubMed1982

Calcium and renin release: inhibition of low sodium-induced renin secretion by high calcium concentration in rat kidney perfusion.

The effects of changes in calcium on renin secretion have been studied in the isolated perfused rat kidney. Perfusion with free calcium buffer significantly decreases renin secretion as compared with control experiments (Ca++: 2.5 mM/l). Other calcium concentrations (1.25 mM/l) and 5 mM/l) do not affect basal renin secretion. When the renin release is previously increased by low sodium concentration (Na+: 110 mM/l) however, perfusion with high calcium buffer (Ca++: 5 mM/l) significantly inhibits this stimulation.

Animals↗
PubMed1980

Evidence for an involvement of acetylcholine in self-stimulation of the prefrontal cortex in the rat.

The effects of injections of antagonists of muscarinic and nicotinic receptors on self-stimulation of the prefrontal cortex in the rat were studied. The results of this investigation suggest that acetylcholine is involved in self-stimulation of the prefrontal cortex through activation of muscarinic receptors, and also suggest a possible interaction between acetylcholine and dopamine in mediating self-stimulation of this area of the brain.

Acetylcholine↗
PubMed1980

The effect of orthostatism, passive tilting and recumbent exercise on renin release.

Three postural tests, orthostatism, passive tilting and recumbent exercise, were applied to fourteen normal volunteers. Orthostatism and tilting produce a significant increase in plasma renin activity (PRA) and plasma renin concentration (PRC), without changes in plasma renin substrate concentration (PSC). Recumbent exercise induces an inhibition of PRA and PRC and does not changes PSC. The present study seems to suggest that sympathetic activity and intravascular blood volume could play an important role in the responses of the renin-angiotensin system to postural changes.

Adult↗
PubMed1979

Effect of sodium and osmolarity on renin secretion.

The effect of changes in sodium and osmolarity on renin secretion has been studied in the isolated perfused rat kidney. Perfusion with low sodium buffer (110 mM/l) produced a significant increase in renin secretion compared with control experiments (Na+:135 mM/l). Since the presence of tubules seems necessary for such an effect to take place, it suggests that the high renin secretion stimulated by a low sodium buffer centers in the Macula densa. Perfusion with high sodium buffer (170 mM/l; osmolarity 350 mOs/l) induces a stimulation on renin release. However, a greater rise in renin is achieved in control experiments if choline chloride increases the osmolarity from 300 to 350 mOs/l. All this suggests that high sodium buffer, independently of its osmotic effect, has an inhibitory role on renin release.

Animals↗
PubMed1978

[Effects of postural changes and volume depletion on renin-angiotensin system (author's transl)].

The effects of orthostatism and furosemide tests on different parameters of renin-angiotensin system have been studied in 14 normal human subjects. Both tests produced a significant increase in plasma renin activity and plasma renin concentration. Plasma substrate concentration was slightly, but significantly, increased on the furosemide test. Plasma aldosterone rose in both tests, while aldosterone urinary excretion decreased after orthostatism and increased after furosemide.

Adult↗
PubMed1977

Stimulation of renin release by prostaglandin E2.

The effect of different doses of prostaglandin E2 on renin secretion in isolated perfused rat kidney has been studied. The infusion of 5 ng/ml of prostaglandin E2 produced a significant rise on renin secretion compared with control group. A dosage increase of prostaglandin E2 (10 and 50 ng/ml) produced an increase in the released renin. From this a correlation between doses and responses can be obtained. The perfusion pressure was slightly--but significantly--modified with the highest dose of prostaglandin (50 ng/ml). The possible pathways of action are dicussed.

Animals↗
PubMedDate not supplied

Differential effects produced by an anticholinergic on the neuroleptic inhibition of motor behaviour and self-stimulation of the prefrontal cortex in the rat.

A specific dopamine receptor blocker, spiroperidol (0.016, 0.032, 0.064 and 0.128 mg/kg) alone or in combined treatment with the centrally acting anticholinergic, dexetimide (0.5, 1.0 mg/kg) was given intraperitoneally to rats pressing a lever for brain self-stimulation through electrodes implanted in the medial prefrontal cortex. The same treatment was also given to rats in which the spontaneous motor behaviour was measured. Spiroperidol produced a dose-related inhibtion of both self-stimulation and spontaneous motor activity. Dexetimide, given to spiroperidol treated rats, was able to antagonize the motor impairment produced by spiroperidol, but prefrontal cortex self-stimulation remained decreased. These data support the suggested role for dopamine in self-stimulation of the prefrontal cortex in the rat.

Animals↗
PubMedDate not supplied

Effects of dietary supplementation with fish oil, lard, or coconut oil on oxytocinase activity in the testis of mice.

Oxytocin (OT), locally synthesized in the testis, is involved in androgen biosynthesis. The use of polyunsaturated fatty acids (e.g., fish oil) in the diet may improve the fertilizing ability in mammals. Cystinyl aminopeptidase (oxytocinase) activity plays a major role regulating the functional status of OT. Sex steroids and the type of the fatty acid used in the diet modify aminopeptidase activities in serum. In the present study, the authors compared the effect of a fish oil supplemented diet with two other diets supplemented with saturated oils (lard and coconut) on oxytocinase activity in the testis of mice. The enzymatic activity was determined fluorometrically using cystinyl-beta-naphthylamide as substrate. The results demonstrated higher levels of oxytocinase activity in mice fed the diet supplemented with fish oil than in those that were fed diets containing lard or coconut oils. The testicular functions in which OT is involved may be attenuated by the use of fish oil in the diet.

Animals↗
PubMedDate not supplied

[Population and development in Mexico: a synthesis of recent experience].

Changes in the relationship between population factors and the development process in Mexico from 1940 to the present are reviewed. The authors show how the development that occurred up to about 1970 both absorbed and encouraged rapid population growth. They then describe how the emergence of problems concerning this relationship led to the development of a population policy during the 1970s. "The paper then takes up the implementation of that policy and the determinants of the fertility decline that took place afterwards, and closes with a brief review of the implications that demographic considerations have for Mexico's future." (SUMMARY IN ENG)

Americas↗
PubMedDate not supplied

[Urban aspects of labor migration: the situation in the countries of origin].

"A bibliographical review serves to analyze the role of urban growth in patterns of international labor-force migration, as well as the effect of this migration on the development of the countries of origin, especially on their cities. While the review confirms the general idea that international migrants are either peasants or highly qualified personnel, it also shows that qualified workers are increasingly involved in international labor movements and that a great part of them come from large cities. It is to be expected that in these circumstances large cities of the countries of origin will become more integrated to international migratory systems." (SUMMARY IN ENG)

Demography↗