In this study, we assessed the possibility that humans differ from other primate species in the supply of dopamine to the frontal cortex. To this end, quantitative comparative analyses were performed among humans, chimpanzees, and macaques using immunohistochemical methods to visualize tyrosine hydroxylase-immunoreactive axons within the cerebral cortex. Axon densities and neuron densities were quantified using computer-assisted stereology. Areas 9 and 32 were chosen for evaluation due to their roles in higher-order executive functions and theory of mind, respectively. Primary motor cortex (area 4) was also evaluated because it is not directly associated with cognition. We did not find an overt quantitative increase in cortical dopaminergic innervation in humans relative to the other primates examined. However, several differences in cortical dopaminergic innervation were observed among species which may have functional implications. Specifically, humans exhibited a sublaminar pattern of innervation in layer I of areas 9 and 32 that differed from that of macaques and chimpanzees. Analysis of axon length density to neuron density among species revealed that humans and chimpanzees together deviated from macaques in having increased dopaminergic afferents in layers III and V/VI of areas 9 and 32, but there were no phylogenetic differences in area 4. Finally, morphological specializations of axon coils that may be indicative of cortical plasticity events were observed in humans and chimpanzees, but not macaques. Our findings suggest significant modifications of dopamine's role in cortical organization occurred in the evolution of the apes, with further changes in the descent of humans.

Tumor necrosis factor alpha (TNFalpha) is a multifunctional cytokine present in oocytes and macrophages in the neonatal rat ovary. The presence of both TNFalpha and its receptors in the neonatal rat ovary suggests a potential role for it in follicle assembly or oocyte atresia. Previous studies have provided support for effects of TNFalpha on isolated granulosa and theca cells and intact follicles; however, to our knowledge, this is the first study to investigate the effects of TNFalpha on the earliest stages of follicular development. Effects of TNFalpha on oocyte/follicle number and apoptosis were investigated using an ovarian organ-culture system that supported assembly of primordial follicles in vitro. Ovaries were collected on the day of birth and treated with TNFalpha (0, 0.1, 1.0, 10, or 50 ng/ml), a function-blocking TNFalpha antibody (5 microg/ml), or control immunoglobulin (Ig) G. At 1 ng/ml, TNFalpha decreased follicle and oocyte numbers during 3 days of culture, whereas higher (10 and 50 ng/ml) or lower (0.1 ng/ml) doses had no effect. Treatment with TNFalpha antibodies increased the number of oocytes and follicles compared to nonspecific IgG control. To determine whether the decreased oocyte/follicle numbers were due to an apoptotic effect of TNFalpha, apoptosis was examined by DNA laddering. At 1 ng/ml, TNFalpha increased apoptotic DNA laddering twofold, with no significant effect from lower or higher doses. The cells undergoing apoptosis, as determined by in situ end-labeling, were oocytes, interstitial cells, and granulosa cells. These findings suggest that TNFalpha may be involved in oocyte atresia that normally occurs during the perinatal period.

Ovarian cells that transcribe and translate the gene for tumor necrosis factor alpha (TNF alpha) were identified in the adult cyclic mouse by using in situ hybridization and immunocytochemistry. TNF alpha mRNA was observed in > 97% and protein was contained in approximately 53% of the oocytes of healthy follicles with two or more layers of granulosa cells, but neither was detectable in oocytes of primordial follicles and follicles with a single layer of granulosa cells. In early atretic follicles, only 13% contained TNF alpha protein and 40% contained TNF alpha mRNA. In late stages of atresia, intense immunoreactive TNF alpha was observed in all of the oocytes, but TNF alpha mRNA was present in only 13%. In approximately 85% of follicles, theca and/or granulosa cells exhibited TNF alpha mRNA hybridization signals. Macrophage-like cells within the interstitium were positive for TNF alpha mRNA and protein. In corpora lutea, luteal cells and macrophage-like cells contained TNF alpha message, while only the latter lineage contained immunoreactive TNF alpha. Hybridization signals and immunoreactivity were more intense in older corpora lutea than in corpora lutea of the present cycle. Northern blot analysis revealed a 2.2-kb TNF alpha mRNA in the ovary that was unchanged relative to 28S rRNA (constitutive RNA) during the cycle. Similarly, TNF alpha hybridization signals and immunoreactivity did not appear to change throughout the cycle. These results indicate that TNF alpha gene transcription in the oocyte coincides with the synthesis of immunoreactive TNF alpha and that these complex biochemical processes occur at distinct steps of follicular development in the mouse.(ABSTRACT TRUNCATED AT 250 WORDS)

In this study, we assess the possibility that the evolution of human intellectual capacities was supported by changes in the supply of serotonin to the frontal cortex. To this end, quantitative comparative analyses were performed among humans, chimpanzees, and macaques. Immunohistochemical methods were used to visualize serotonin transporter-immunoreactive (SERT-ir) axons within the cerebral cortex. Areas 9 and 32 were chosen for evaluation due to their roles in working memory and theory of mind, respectively. Primary motor cortex was also evaluated because it is not associated with higher cognitive functions. The findings revealed that humans do not display a quantitative increase in serotonin innervation. However, the results indicated region- and layer-specific differences among species in serotonergic innervation pattern. Compared with macaques, humans and chimpanzees together displayed a greater density of SERT-ir axons relative to neuron density in layers V/VI. This change was detected in cortical areas 9 and 32, but not in primary motor cortex. Further, morphological specializations, coils of axons, were observed in humans and chimpanzees that were absent in macaques. These features may represent a greater capacity for cortical plasticity exclusive to hominoids. Taken together, these results indicate a significant reorganization of cortical serotonergic transmission in humans and chimpanzees.

Tumor necrosis factor alpha (TNF alpha) has previously been immunolocalized within mouse oocytes. Our first objective was to examine TNF alpha immunolocalization in ovaries of adult, fetal, and neonatal rats. Our second objective was to examine TNF alpha mRNA in ovaries by Northern blot analysis and in oocytes by reverse-transcriptase polymerase chain reaction (RT-PCR). Our final objective was to determine whether oocytes contained bioactive TNF alpha. Ovaries and oviducts were collected throughout the estrous cycle in adult rats, fetal ovaries were obtained 1 day before expected delivery, and neonatal ovaries were collected 2 days after birth. TNF alpha was localized in tissues by a biotin-avidin immunocytochemical procedure. Immunocytochemistry in adult ovaries showed that the ooplasm of the oocyte was the primary site of TNF alpha localization within the follicle. Immunostaining was present in all oocytes in the adult, including ovulated oocytes within the oviduct. Oocytic TNF alpha immunostaining was also present within oocytes in the neonate; however, fetal oocytes did not contain immunoreactive TNF alpha. Northern blots showed that ovaries in the adult, neonate, and fetus all contained TNF alpha mRNA. RT-PCR analysis of oocytes collected from preovulatory follicles generated a cDNA band of 500 bp, corresponding to the predicted size for amplified TNF alpha cDNA. Subsequent Southern blot analysis showed that the 500-bp band hybridized to the TNF alpha probe, indicating that preovulatory oocytes contain TNF alpha mRNA. Preovulatory oocytes were used in TNF alpha cytotoxicity assays with L929 cells. Oocytes contained TNF alpha bioactivity that was similar to that of recombinant murine TNF alpha in the bioassay. Our results provide evidence for the identification of immunoreactive and bioactive TNF alpha within oocytes in the rat, which is further supported by the presence of TNF alpha mRNA within the oocyte. These studies also indicate that TNF alpha may appear in the oocyte around the time of birth.