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At least 325 records · Page 18Linked to original sources
PubMed2007

Brewing controversies: Darwinian perspective on the adaptive and maladaptive effects of caffeine and ethanol as dietary autonomic modulators.

Ethanol and caffeine are two of the oldest human drugs. Their pervasive integration into the modern human diet may reflect behavioral attempts to correct maladaptations induced by evolutionary displacement of the autonomic system. The dietary adoption of caffeine may parallel the emergence of cognition as an independent basis of competition. Enhancement of the cognitive ability to gather and process information likely evolved as a valuable adjunct to physical behavior in prehistoric fight-or-flight encounters. Caffeine effectively exploits this pre-existing association between adrenergic activity and cognitive readiness, leading to its use in the modern environment where success in competition increasingly depends on cognitive, rather than physical, prowess. Ethanol may have emerged as a dietary means to buffer the maladaptive chronic sympathetic activation and fear response associated with stressful lifestyles and the social phobias associated with the dissolution of kin networks. We explore the health implications of ethanol and caffeine use, with particular attention to their acute and chronic effects on the autonomic axis. The putative protective effects of ethanol in surviving major trauma or reducing inflammation and heart disease may relate to tempering the behavioral and cardiovascular consequences of catastrophic or chronic sympathetic activation. Acute or chronic abuse of ethanol manifests paradoxical pro-adrenergic effects such as tremors and insomnia that may partly represent compensatory responses. Compensatory remodeling may also explain why confirmation of detrimental effects related to caffeine-induced sympathetic activation has proven elusive; indeed, paradoxical pro-vagal benefits may eventually be recognized. Ethanol and caffeine are potential agents that may beneficially expand the dynamic range of the autonomic system. In an environment where the Darwinian value of knowledge has increasingly supplanted that of physical traits, the consumption of caffeine and alcohol may represent both a cause and an effect of modern human evolution.

Adaptation, Physiological↗
PubMed1995

Organismal duplication, inclusive fitness theory, and altruism: understanding the evolution of endosperm and the angiosperm reproductive syndrome.

For almost a century, events relating to the evolutionary origin of endosperm, a unique embryo-nourishing tissue that is essential to the reproductive process in flowering plants, have remained a mystery. Integration of recent advances in phylogenetic reconstruction, comparative reproductive biology, and genetic theory can be used to elucidate the evolutionary events and forces associated with the establishment of endosperm. Endosperm is shown to be derived from one of two embryos formed during a rudimentary process of "double fertilization" that evolved in the ancestors of angiosperms. Acquisition of embryo-nourishing behavior (with accompanying loss of individual fitness) by this supernumerary fertilization product was dependent upon compensatory gains in the inclusive fitness of related embryos. The result of the loss of individual fitness by one of the two original products of double fertilization was the establishment of endosperm, a highly modified embryo/organism that reproduces cryptically through behavior that enhances the fitness of its associated embryo within a seed. Finally, although triploid endosperm remains a synapomorphy of angiosperms, inclusive fitness analysis demonstrates that the embryo-nourishing properties of endosperm initially evolved in a diploid condition.

Journal Article↗
PubMed1996

Immunologic dissonance: a continuing evolution in our understanding of the systemic inflammatory response syndrome (SIRS) and the multiple organ dysfunction syndrome (MODS)

Our current understanding of sepsis and multiple organ dysfunction needs to be revised, as the uniformly negative results of new therapies for these disorders suggest. Previous theories for the pathogenesis of these conditions are incomplete; reasons for this include the following. First, the surrogate models that have been used to study these disorders are not analogous to the clinical situation. Second, patients who have less severe manifestations of these diseases are often overlooked. And third, patients' preexisting conditions have not been taken into account. Considerable new evidence indicates that, in addition to a massive proinflammatory reaction, a compensatory anti-inflammatory response contributes to the onset of these disorders. At a local site of injury or infection and during the initial appearance of pro- and anti-inflammatory mediators in the circulation, the beneficial effects of these mediators outweigh their harmful effects. Only when the balance between these two forces is lost do these mediators become harmful. Sequelae of an unbalanced systemic proinflammatory reaction include shock, transudation into organs, and defects in coagulation. An unbalanced systemic compensatory anti-inflammatory response can result in anergy and immunosuppression. The proinflammatory and anti-inflammatory forces may ultimately reinforce each other, creating a state of increasingly destructive immunologic dissonance.

Humans↗
PubMed2004

A longitudinal fMRI study: in recovering and then in clinically stable sub-cortical stroke patients.

The aim of this 1-year longitudinal fMRI study was to compare hand motor activation patterns between cerebrovascular paretic patients with a subcortical infarction and healthy elderly subjects and to evaluate the changes between the subacute phase and the chronic phase of recovery. We studied eight right-handed patients with pure motor hemiparesis due to a single ischemic infarct of the corticospinal tract. Each patient underwent a first fMRI (E1) 20 +/- 9 days after stroke, a second (E2) after 4 months and a third (E3) 12 months after stroke. During each fMRI session, the patients performed an active motor task consisting of audio-paced (1 Hz) finger flexion-extension of the paretic hand and underwent a passive motor task consisting of flexion-extension of the paretic hand performed by an examiner. Data were analyzed with SPM99 (random effect analyses). Patients had recovered at E2, were stable between E2 and E3, but still experienced a hand weakness. Displacement of activation maxima coordinates in patients compared to healthy subjects suggested an early reorganization within the SMA and a secondary reorganization within the ipsilesional S1M1 at E2. The main differences between patients and healthy subjects were (1) recruitment of the posterior part of the cingulate cortex and SMA, (2) a general hyperactivation (except in the deefferented primary motor cortex) and (3) an evolution in the S1M1 activation from an early (20 days after stroke) contralesional hyperactivation to a later (4 months after stroke) ipsilesional hyperactivation concomitant to recovery. Changes in activation were confirmed by the passive task that involved no effort and little attention. Despite clinical stability, changes in brain processing seemed to occur between E2 and E3 corresponding to a normalization of ipsilesional S1M1 activation, a decrease of bilateral cerebellar activation, and a progressive increase in SII-BA 40 activity suggesting evolving compensatory networks to sustain recovery.

Adult↗
PubMed2004

Nuclear medicine dynamic investigations of diffuse chronic liver diseases and portal hypertension.

Radio-isotopic techniques may be useful in diagnosis and staging of chronic diffuse liver diseases. Liver angioscintigraphy (LAS) and per-rectal portal scintigraphy (PRPS) are at well discriminating portal hypertension (PHT), very early cirrhosis hemodynamic failure and compensatory arterialisation of liver perfusion. Supplied information is related to PHT, liver morphology and mesenchimal activity in liver, spleen and bone marrow. Correlation of LAS and PRPS may diagnose installing of PHT earlier than any actual morphologic imagistic method. Our experience (after more than 300 PRPS and 500 LAS) suggests that PHT and portal-cave shunts (PCS) may be classified in five functional stages. These five patterns (types) are characteristic for portal dynamics, supporting disease staging and follow-up of evolution to cirrhosis. All five dynamics may be assessed by PRPS and LAS. Scintigraphic techniques also explore portal thromboses, perfusion differences between the lobes of cirrhotic liver, betablockers effect in PHT, earliest stages of PHT, malignant tumours occurring on cirrhosis, the different characteristics of alcoholic liver comparing to viral etiology.

Hepatitis, Chronic↗
PubMed1999

High sequence turnover in the regulatory regions of the developmental gene hunchback in insects.

Extensive sequence analysis of the developmental gene hunchback and its 5' and 3' regulatory regions in Drosophila melanogaster, Drosophila virilis, Musca domestica, and Tribolium castaneum, using a variety of computer algorithms, reveals regions of high sequence simplicity probably generated by slippage-like mechanisms of turnover. No regions are entirely refractory to the action of slippage, although the density and composition of simple sequence motifs varies from region to region. Interestingly, the 5' and 3' flanking regions share short repetitive motifs despite their separation by the gene itself, and the motifs are different in composition from those in the exons and introns. Furthermore, there are high levels of conservation of motifs in equivalent orthologous regions. Detailed sequence analysis of the P2 promoter and DNA footprinting assays reveal that the number, orientation, sequence, spacing, and protein-binding affinities of the BICOID-binding sites varies between species and that the 'P2' promoter, the nanos response element in the 3' untranslated region, and several conserved boxes of sequence in the gene (e.g., the two zinc-finger regions) are surrounded by cryptically-simple-sequence DNA. We argue that high sequence turnover and genetic redundancy permit both the general maintenance of promoter functions through the establishment of coevolutionary (compensatory) changes in cis- and trans-acting genetic elements and, at the same time, the possibility of subtle changes in the regulation of hunchback in the different species.

Amino Acid Sequence↗
PubMed1995

Molecular evolution of the mitochondrial 12S rRNA in Ungulata (mammalia).

The complete 12S rRNA gene has been sequenced in 4 Ungulata (hoofed eutherians) and 1 marsupial and compared to 38 available mammalian sequences in order to investigate the molecular evolution of the mitochondrial small-subunit ribosomal RNA molecule. Ungulata were represented by one artiodactyl (the collared peccary, Tayassu tajacu, suborder Suiformes), two perissodactyls (the Grevy's zebra, Equus grevyi, suborder Hippomorpha; the white rhinoceros, Ceratotherium simum, suborder Ceratomorpha), and one hyracoid (the tree hyrax, Dendrohyrax dorsalis). The fifth species was a marsupial, the eastern gray kangaroo (Macropus giganteus). Several transition/transversion biases characterized the pattern of changes between mammalian 12S rRNA molecules. A bias toward transitions was found among 12S rRNA sequences of Ungulata, illustrating the general bias exhibited by ribosomal and protein-encoding genes of the mitochondrial genome. The derivation of a mammalian 12S rRNA secondary structure model from the comparison of 43 eutherian and marsupial sequences evidenced a pronounced bias against transversions in stems. Moreover, transversional compensatory changes were rare events within double-stranded regions of the ribosomal RNA. Evolutionary characteristics of the 12S rRNA were compared with those of the nuclear 18S and 28S rRNAs. From a phylogenetic point of view, transitions, transversions and indels in stems as well as transversional and indels events in loops gave congruent results for comparisons within orders. Some compensatory changes in double-stranded regions and some indels in single-stranded regions also constituted diagnostic events. The 12S rRNA molecule confirmed the monophyly of infraorder Pecora and order Cetacea and demonstrated the monophyly of the suborder Ruminantia was not supported and the branching pattern between Cetacea and the artiodacytyl suborders Ruminantia and Suiformes was not established. The monophyly of the order Perissodactyla was evidenced, but the relationships between Artiodactyla, Cetacea, and Perissodactyla remained unresolved. Nevertheless, we found no support for a Perissodactyla + Hyracoidea clade, neither with distance approach, nor with parsimony reconstruction. The 12S rRNA was useful to solve intraordinal relationships among Ungulata, but it seemed to harbor too few informative positions to decipher the bushlike radiation of some Ungulata orders, an event which has most probably occurred in a short span of time between 55 and 70 MYA.

Animals↗
PubMed1991

Reconstruction and analysis of human Alu genes.

The existing classification of human Alu sequences is revised and expanded using a novel methodology and a larger set of sequence data. Our study confirms that there are two major Alu subfamilies, Alu-J and Alu-S. The Alu-S subfamily consists of at least five distinct subfamilies referred to as Alu-Sx, Alu-Sq, Alu-Sp, Alu-Sc, and Alu-Sb. The Alu-Sp and Alu-Sq subfamilies have been revealed by this study. Alu subfamilies differ from one another in a number of positions called diagnostic. In this paper the diagnostic positions are defined in quantitative terms and are used to evaluate statistical significance of the observed subfamilies. Each Alu subfamily most likely represents pseudogenes retroposed from evolving functional source Alu genes. Evidence presented in this paper indicates that Alu-Sp and Alu-Sc pseudogenes were retroposed from different source genes, during overlapping periods of time, and at different rates. Our analysis also indicates that the previously identified Alu-type transcript BC200 comes from an active Alu gene that might have existed even before the origin of dimeric Alu sequences. The source genes for Alu pseudogene families are reconstructed. It is assumed that diagnostic differences between reconstructed source genes reflect mutations that have occurred in true source Alu genes under natural selection. Some of these mutations are compensatory and are used to reconstruct a common secondary structure of Alu RNAs transcribed from the source genes. The biological function of Alu RNA is discussed in the context of its homology to the elongation-arresting domain of 7SL RNA.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed2004

Distinct patterns of natural selection in the reverse transcriptase gene of HIV-1 in the presence and absence of antiretroviral therapy.

The emergence of human immunodeficiency virus (HIV) drug-resistant mutations during antiretroviral therapy is explained by either the preexistence of low-frequency-resistant strains before the start of therapy or by the selection of unsuppressed resistant strains during therapy. We used pairwise and maximum likelihood analyses of the ratio of nonsynonymous to synonymous substitutions per site (d(N)/d(S)) to study the extent of positive selection in the reverse transcriptase (RT) gene of HIV-1 from multiple data sets of drug-treated (117 sequences) and drug-naive patients (270 sequences). In the pairwise analysis, evidence for positive selection (d(N)/d(S) > 1) was only found in drug-treated individuals and in codons conferring drug resistance. By the maximum likelihood method, a positive selection at codons conferring drug resistance was only observed in patients receiving therapy, and although positive selection was detected in drug-naive patients, this was always at codons unrelated to drug resistance. We therefore document a striking difference in the process of allele fixation in drug resistance codons (RC) between populations of HIV-1-infected individuals naive to treatment and those receiving therapy. Furthermore, although mutations associated with drug resistance are sometimes found in drug-naive patients, we suggest that these are fixed because of linkage to sites experiencing immune escape. Finally, we show that compensatory changes are likely to be important in the development of HIV drug resistance by counter-acting the deleterious effects normally associated with drug resistance mutations.

Amino Acid Sequence↗
PubMed2005

An evolutionary intra-molecular shift in the preferred U3 snoRNA binding site on pre-ribosomal RNA.

Correct docking of U3 small nucleolar RNA (snoRNA) on pre-ribosomal RNA (pre-rRNA) is essential for rRNA processing to produce 18S rRNA. In this report, we have used Xenopus oocytes to characterize the structural requirements of the U3 snoRNA 3'-hinge interaction with region E1 of the external transcribed spacer (ETS) of pre-rRNA. This interaction is crucial for docking to initiate rRNA processing. 18S rRNA production was inhibited when fewer than 6 of the 8 bp of the U3 3'-hinge complex with the ETS could form; moreover, base pairing involving the right side of the 3'-hinge was more important than the left. Increasing the length of the U3 hinge-ETS interaction by 9 bp impaired rRNA processing. Formation of 18S rRNA was also inhibited by swapping the U3 5'- and 3'-hinge interactions with the ETS or by shifting the base pairing of the U3 3'-hinge to the sequence directly adjacent to ETS region E1. However, 18S rRNA production was partially restored by a compensatory shift that allowed the sequence adjacent to the U3 3'-hinge to pair with the eight bases directly adjacent to ETS region E1. The results suggest that the geometry of the U3 snoRNA interaction with the ETS is critical for rRNA processing.

Animals↗
PubMed1976

[Morphofunctional specialization of tissue components of the mammalian placenta and adaptational value in changes in the rate of their differentiation (evolutionary and clinical aspects)].

It has been shown that in the ontogenesis of human placenta there occur regular changes in the percentage of the villi of various calibre having different interrelationships between the trophoblast, the connective tissue stroma and the fetal vessel. The changes of the number of chorial villi affected by fibrinoid and containing blood vessels under the trophoblast in late toxicoses of women and the anemic syndrom are analyzed (treated and not treated groups of women suffering from different forms of toxicosis were compared). An increased amount of chorial villi having blood vessels under the trophoblast is noted which is a morphofunctional feature of compensatory-adaptational alterations. Possible ecologo-evolutionary approaches to clearing the biological significance of adaptational changes of morphogenesis of the human placenta in pathological pregnancy are shown by the example of the analysis of morphological peculiarities of the placenta of the dolphin.

Adaptation, Physiological↗
PubMed1999

Evolution of the mitochondrial rps3 intron in perennial and annual angiosperms and homology to nad5 intron 1.

The plant mitochondrial rps3 intron was analyzed for substitution and indel rate variation among 15 monocot and dicot angiosperms from 10 genera, including perennial and annual taxa. Overall, the intron sequence was very conserved among angiosperms. Based on length polymorphism, 10 different alleles were identified among the 10 genera. These allelic differences were mainly attributable to large indels. An insertion of 133 nucleotides, observed in the Alnus intron was partially or completely absent in the other lineages of the family Betulaceae. This insertion was located within domain IV of the secondary-structure model of this group IIA intron. A mobile element of 47 nucleotides that showed homology to sequences located in rice rps3 intron and in intergenic plant mitochondrial genomes was found within this insertion. Both substitution and indel rates were low among the Betulaceae sequences, but substitution rates were increasingly larger than indel rates in comparisons involving more distantly related taxa. From a secondary-structure model, regions involved in helical structures were shown to be well preserved from indels as compared to substitutions, but compensatory changes were not observed among the angiosperm sequences analyzed. Using approximate divergence times based on the fossil record, substitution and indel rate heterogeneity was observed between different pairs of annual and perennial taxa. In particular, the annual petunia and primrose evolved more than 15 and 10 times faster, for substitution and indel rates respectively, than the perennial birch and alder. This is the first demonstration of an evolutionary rate difference between perennial and annual forms in noncoding DNA, lending support to neutral causes such as the generation time, population size, and speciation rate effects to explain such rate heterogeneity. Surprisingly, the sequence from the rps3 intron had a high identity with the sequence of intron 1 from the angiosperm mitochondrial nad5 gene, suggesting a common origin of these two group IIA introns.

Base Sequence↗
PubMed1990

Neurotransmitters and stress.

In this article definitions of stress and distress are proposed and the relationships between stress and activities of neurohormonal systems explored. The idea is developed that stress is a condition where expectations--whether genetically programmed, established by prior learning, or deduced from circumstances--do not match the current or anticipated perceptions of the internal or external environment, and this discrepancy between what is observed or sensed and what is expected or programmed elicits patterned, compensatory responses. Distress is viewed here as a form of stress characterized by specific behavioral and autonomic communicated signs, pituitary-adrenocortical and sympathoadrenomedullary activation, and a negative experience that motivates escape or avoidance. During stress, many body systems--including the sympathoadrenal, parasympathetic, and hormonal homeostatic systems--are activated or inhibited in primitively specific patterns regulated by physiological, biochemical, and psychological homeostats. Many of these patterns, which are at least partly inherited, can be understood teleologically on the basis of preservation of the internal environmental and natural selection in evolution.

Animals↗
PubMed1997

Intron self-complementarity enforces exon inclusion in a yeast pre-mRNA.

Skipping of internal exons during removal of introns from pre-mRNA must be avoided for proper expression of most eukaryotic genes. Despite significant understanding of the mechanics of intron removal, mechanisms that ensure inclusion of internal exons in multi-intron pre-mRNAs remain mysterious. Using a natural two-intron yeast gene, we have identified distinct RNA-RNA complementarities within each intron that prevent exon skipping and ensure inclusion of internal exons. We show that these complementarities are positioned to act as intron identity elements, bringing together only the appropriate 5' splice sites and branchpoints. Destroying either intron self-complementarity allows exon skipping to occur, and restoring the complementarity using compensatory mutations rescues exon inclusion, indicating that the elements act through formation of RNA secondary structure. Introducing new pairing potential between regions near the 5' splice site of intron 1 and the branchpoint of intron 2 dramatically enhances exon skipping. Similar elements identified in single intron yeast genes contribute to splicing efficiency. Our results illustrate how intron secondary structure serves to coordinate splice site pairing and enforce exon inclusion. We suggest that similar elements in vertebrate genes could assist in the splicing of very large introns and in the evolution of alternative splicing.

Exons↗
PubMed2001

Body building and concurrent mass loss: flight adaptations in tree sparrows.

Environmental changes are responsible for the evolution of flexible physiology and the extent of phenotypic plasticity in the regulation of birds' organ size has not been appreciated until recently. Rapid reversible physiological changes during different life-history stages are virtually only known from long-distance migrants, and few studies have focused on less extreme aspects of organ flexibility. During moult, birds suffer from increased wing loading due to wing-area reductions, which may impair flight ability. A previous study found that tree sparrows' escape flight (Passer montanus) is unaffected during moult, suggesting compensatory aptness. We used non-invasive techniques to study physiological adaptations to increased wing loading in tree sparrows. As wing area was reduced during natural moult the ratio of pectoral-muscle size to body mass increased. When moult was completed this ratio decreased. We show experimentally a novel, strategic, organ-flexibility pattern. Unlike the general pattern, where body mass is positively coupled to pectoral-muscle size, tree sparrows responded within 7 days to reductions in wing area by reducing body mass concurrently with an increase in pectoral-muscle size. This rapid flexibility in a non-migratory species probably reflects the paramount importance and long history of flight in birds.

Adaptation, Physiological↗
PubMedDate not supplied

[Human hemoglobin: polymorphism, neutrality of variants, evolutionary aspect].

Integrated analysis of the polymorphism of human hemoglobin has been made using populational genetics, hematological, physiological, protein chemistry and molecular biology data. The known variants of human hemoglobin are conventionally classified as "widely common", "less common" and "rare", depending on their contribution to polymorphism. The importance of homeostasis and compensatory reactions for maintaining the resistance of the human body against mutant hemoglobins is emphasized. Hb D Punjab and Hb O Arab being relatively neutral, the genetic structure of populations may restrict their distribution. A hypothesis is put forward concerning the possible role of an increased local conformational mobility of protein in creating neutral protein variants. It is proposed to discriminate between truly neutral and pseudoneutral protein variants. In case of possible changes in the genetic and environmental factors, the former are not subject to selection, while the latter may be. Contribution to neutral evolution can be made only by truly neutral variants. In a compensated heterozygotic state the truly neutral and pseudoneutral variants may give rise to new functions and adaptively valuable properties in protein. The evolution of proteins is believed to proceed from a stage which is consistent with M. Kimura's concept of neutrality of protein polymorphism toward a stage which is consistent with the concept of selectionism. It is concluded, that the currently observed degree of polymorphism of human hemoglobin corresponds to the present stage of molecular evolution of the protein.

Biological Evolution↗
PubMed2006

Reducing the fitness cost of antibiotic resistance by amplification of initiator tRNA genes.

Deformylase inhibitors belong to a novel antibiotic class that targets peptide deformylase, a bacterial enzyme that removes the formyl group from N-terminal methionine in nascent polypeptides. Using the bacterium Salmonella enterica, we isolated mutants with resistance toward the peptide deformylase inhibitor actinonin. Resistance mutations were identified in two genes that are required for the formylation of methionyl (Met) initiator tRNA (tRNAi)(fMet): the fmt gene encoding the enzyme methionyl-tRNA formyltransferase and the folD gene encoding the bifunctional enzyme methylenetetrahydrofolate-dehydrogenase and -cyclohydrolase. In the absence of antibiotic, these resistance mutations conferred a fitness cost that was manifested as a reduced growth rate in laboratory medium and in mice. By serially passaging the low-fitness mutants in growth medium without antibiotic, the fitness costs could be partly ameliorated either by intragenic mutations in the fmt/folD genes or by extragenic compensatory mutations. Of the extragenically compensated fmt mutants, approximately one-third carried amplifications of the identical, tandemly repeated metZ and metW genes, encoding tRNAi. The increase in metZW gene copy number varied from 5- to 40-fold and was accompanied by a similar increase in tRNAi levels. The rise in tRNAi level compensated for the lack of methionyl-tRNA formyltransferase activity and allowed translation initiation to proceed with nonformylated methionyl tRNAi. Amplified units varied in size from 1.9 to 94 kbp. Suppression of deleterious mutations by gene amplification may be involved in the evolution of new gene functions.

Amidohydrolases↗
PubMed1996

Effects of prenatal exposure to amphetamine in the medial prefrontal cortex of the rat.

This study was designed to investigate the effects of prenatal exposure to amphetamine in the organization of the medial prefrontal cortex of the rat, by an evaluation of growth, morphometric and neurochemical parameters. Pregnant Wistar rats were given 10 mg/kg body weight/day of D-amphetamine sulfate, subcutaneously, from gestational days 8 to 22. Control groups of pregnant rats were injected with saline, pair-fed or non-manipulated; litters were culled to eight pups (four males and four females), weighed every other day until postnatal day 30 and every week until day 90. The Gompertz model was used to study body weight evolution and the estimated growth parameters were not significantly different in the experimental groups. At postnatal days 14 and 30, the volumes of the prefrontal cortex, the fraction of neuropile occupied by neurons and the number of neurons per unit surface are were determined. The number of neurons per unit volume of reference area was calculated using the stereological technique of the dissector. For neurochemical analysis, the medial prefrontal cortex was dissected to measure the concentration of dopamine, serotonin and their metabolites. The allometric relationship of forebrain/body growth pointed to a mechanism of sparing and compensatory growth in the amphetamine exposed group. The changes found in the number of neurons per unit volume at postnatal day 14 show a catch-up at postnatal day 30. A decrease in serotonin levels was found in the amphetamine group compared with the pair-fed control, which was reflected in the ratio of serotonin to its metabolite, 5-hydroxyindolacetic acid. These changes, whether permanent or transitory, raise the possibility that some of the effects of prenatal exposure to amphetamine may be due to modifications in the neurotransmitter levels of serotonin.

Amphetamine↗