Ventricular system of the brain of the dolphin, Tursiops truncatus, with comparative anatomical observations and relations to brain specializations

A comparative and quantitative anatomical study of the cerebral ventricular system of the dolphin, Tursiops truncatus, and six other mammalian species, including man, has been made in the course of extensive neuroanatomical investigations of the dolphin. Several techniques have been used in these studies to confirm the morphological arrangement and contours of the ventricles. Casts of the ventricles were produced by use of a variety of casting media and methods and their relative merits were investigated and described. Following injection of the brain with casting media, the brain was either totally removed by dissection or digestion or one hemisphere dissected away to reveal the relationships of the ventricular cast to the opposite cerebral hemisphere. Serial sections of the brains of three dolphins were cut in three cardinal planes, and from these a model of the entire ventricular system was reconstructed. Serial sections (Nissl and Loyez) were also used to identify structures closely related to the ventricular cavities. Our results show that components of the cerebral ventricular system of the dolphin reflect, to a considerable degree, many of the specialized features of that brain including brachycephaly, widened and foreshortened temporal lobes, large limbic lobe, hypodeveloped frontal region, absence of an occipital pole, and massive development of the tectal acoustic apparatus. The morphological characteristics of the ventricular system and the relationship of this system to brain areas is discussed with respect to possible functional and phylogenetic implications.     

Ultrastructure of synapses and golgi analysis of neurons in neocortex of the lateral gyrus (visual cortex) of the dolphin and pilot whale

Qualitative and computerized quantitative analyses of ultrastructural features of synapses in different layers of the primary visual cortex in the dolphin (Stenella coeruleoalba) and the pilot whale (Globicephala melaena) were carried out. Also, Golgi and cytoarchitectonic analyses were performed in the same species of cetaceans and, additionally, in Tursiops truncatus and Phocaena phocaena. It was found that on a synaptic level, as well as in cytoarchitectonic and Golgi features, the neocortex of cetaceans combines evolutionary progressive features and conservative features with a marked prevalence of the latter. Thus, the total number of synapses in visual neocortex in cetaceans is closer to this value in higher Primates. On the other hand, the laminar density of synapses per mm3 is generally the same in all layers in cetacean visual cortex and numerically is close to values found in small lissencephalic brains. Also, the synapse/neuron ratio in the dolphin visual cortex is of the same order as in cortices of rodents and lagomorphs and much higher than in cortices of advanced terrestrial mammals. Layers I and II contain approximately 70% of the total synapses in the cortical slab through visual cortex. Layer I also contains the extraverted dendrites of neurons of layer II and thus these two layers resemble a paleoarchicortical type of organization superimposed on a more typical neocortical organization of the lower cortical layers. In this respect the convexity neocortex of cetaceans is generally similar to the neocortices of phylogenetically ancient extant mammals such as basal Insectivora and Chiroptera.     

Multi-element screening by ICP-MS of two specimens of Napoleon's hair

Since 1960, it has been demonstrated by various analytical procedures that high concentrations of arsenic were present in Napoleon's hair. Various authors, indicating that the detected arsenic levels are a consequence of external contamination, have challenged the results of these examinations. In order to shed more light on this historical controversy, we have tested two samples of Napoleon's hair by inductively coupled plasma-mass spectrometry (ICP-MS). The samples of hair were decontaminated with acetone and were cut into small segments. For multi-element screening, hair samples were mineralized in concentrated nitric acid for 1 h at 70 degrees C, diluted 1:40 in specific solution with rhodium as an internal standard, and finally analyzed by ICP-MS on a Thermo Electron ICP/MS X7. Multi-element analysis of Napoleon's hair samples revealed massive amounts of arsenic (42.1 and 37.4 ng/mg), antimony (2.1 and 1.8 ng/mg) and elevated levels of mercury (3.3 and 4.7 ng/mg) and lead (229 and 112 ng/mg). In the case of arsenic, these concentrations, 40 times higher than the normal values, confirm the hypothesis of a significant exposure to arsenic. The concentrations of the other elements, in particular antimony and mercury, are in agreement with the data already known about the therapeutic treatments given to Napoleon, which were based on calomel (salt of mercury) and tartar emetic (antimony).     

Effects of growth hormone on brain biogenic amine levels.

The effects of IP administered bovine growth hormone (GH) on regional brain serotonin, 5-hydroxyindoleacetic acid (5-HIAA) and norepinephrine levels in rats were examined. GH decreased the levels of both monoamines and 5-HIAA in the diencephalon and brainstem while not affecting telencephalic concentrations. In hypophysectomized rats, however GH produced significant elevations of monoamine and 5-HIAA levels in all brain regions. In normal rats the decreases in norepinephrine content produced by GH were correlated with a reduction in the stimulatory action of d-amphetamine on general activity levels. These results demonstrate that GH can affect brain biogenic amines and that these effects have behavioral consequences.     

Sleep-waking patterns in cats after administration of fenfluramine and other monoaminergic modulating drugs

Fenfluramine produced a dose-dependent, biphasic effect on sleep-waking patterns in cats. At low doses (0.4 mg/kg) fenfluramine elicited an increase in total waking time and a marked reduction in REM sleep, similar to that seen after administration of amphetamine, without affecting SWS. At anorectic doses (5.0 mg/kg) fenfluramine almost completely suppressed REM sleep, reduced waking time and increased SWS, an effect similar to that seen after administration of 5-HTP, the precursor of serotonin. The fenfluramine-induced increase in SWS was facilitated by 5-HTP and blocked by LSD, a serotonin antagonist. Serotonin was significantly reduced in the neocortex, pyriform lobe, cerebellum and hindbrain at the time of the drug's peak effect on SWS suggesting that the fenfluramine-induced increase in SWS is mediated via serotonin dependent mechanisms.     

The effects of protein malnutrition on the developing central nervous system in the rat

We have carried out a multi-disciplinary study of the effects of prenatal protein malnutrition on the developing rat brain. These experiments, involving anatomical, physiological, biochemical, and behavioral approaches, have revealed that malnutrition induced prenatally can affect various parameters of brain growth and development. Some of these effects can be reversed depending on when dietary restitutions are carried out. However, if protein malnutrition is maintained during the brain growth spurt or critical growth periods there are many permanent sequelae that cannot be reversed by subsequent restitution of high protein diets. We have reviewed the concept of critical periods of brain growth relative to the various aspects of neural morphogenesis in the rat, that is, the birth of neurons, migration of neurons, differentiation of neurons, and synapse formation. We have also discussed the rapid phases of brain growth in the rat as compared to similar phases in other species as a basis for determining whether the rat model can provide time-tables for brain growth in other species, including man. Different components of the brain, both morphological and chemical, have their own cycles of rapid development so that insults to the brain at particular periods affect particular aspects of brain chemistry and neuronal systems. Development of chemical circuits in the brain, such as the aminergic neurons, and their eventual adequate functioning, depends on development of the neurotransmitters themselves. These latter are markedly affected by protein malnutrition. Major physiological-behavioral states, such as the sleep-waking continuum, are markedly affected by protein malnutrition as are many behaviors. Some of these latter are merely late or retarded in development but others remain permanently altered. By approaching the problem of protein malnutrition from multiple points of view we have been able to pinpoint several brain areas showing the most drastic residua of early protein malnutrition and are beginning, by use of morphometric, electro-ontogenetic, biochemical development and behavioral studies, to define brain locales and basic mechanisms by which these insults produce their effects.     

The effects of protein deprivation on the nucleus locus coeruleus: A morphometric golgi study in rats of three age groups

In a previous morphometric Golgi study of the nucleus locus coeruleus we identified in rats fed a 25% casein diet 3 cell types, fusiform, multipolar and ovoid, and compared their age-related changes from 30 to 90 days and 90 to 220 days. In the present study we investigated the effects of an 8% casein diet, initiated prenatally and continued postnatally in the pups, using the same morphometric parameters at the same 3 ages. In these rats the majority of significant age-related changes were in primary and secondary dendritic spine density. On all 3 cell types between 30 and 90 days there was a decreased spine density followed by an increase between 90 and 220 days. These age-related changes closely followed those in controls and, as a result, when the two diet groups were compared at each age they showed only 4 significant differences out of 18 comparisons. In control rats these age-related changes in dendritic spine density in the nucleus locus coeruleus were diametrically out-of-phase with those found in the nucleus raphe dorsalis in a previous study. This is consistent with the postulated mutual inhibitory relationship between the nucleus locus coeruleus and nucleus raphe dorsalis. Comparison of these same events in the nucleus locus coeruleus and nucleus raphe dorsalis in the 8% casein diet rats show no evidence of an out-of-phase relationship. Thus, the relationship between these two closely related nuclei appears to be fundamentally altered by the 8% casein diet. In these comparisons of dendrite spine density and other parameters the 8% casein diet rats have shown in both the nucleus locus coeruleus and nucleus raphe dorsalis deficits and increases as compared to controls. In contrast, in morphometric Golgi studies of pyramidal and Purkinje cells undernutrition generally results in deficits or little change in the various parameters. This suggests that the adaptation of the non-pyramidal neurons in the present study is different from that shown by pyramidal and Purkinje cells.