Transgenerational effects of maternal exposure to nicotine on structures of pituitary-gonadal axis of rats.

Smoking can lead to several diseases and cause a reduction in fertility in men and women. Among the various components of cigarettes harmful during pregnancy, nicotine stands out. It can cause a reduction in placental blood flow, compromising the development of the baby with neurological, reproductive and endocrine consequences. Thus, we aimed to evaluate the effects of nicotine on the pituitary-gonadal axis of rats exposed during pregnancy and breastfeeding (1st generation - F1), and whether the possible damage observed would reach the 2nd generation (F2). Pregnant Wistar rats received 2 mg/kg/day of nicotine throughout the entire gestation and lactation. Part of the offspring was evaluated on the first neonatal day (F1) for macroscopic, histopathological and immunohistochemical analyses of brain and gonads. Another part of the offspring was kept until 90 days-old for mating and obtainment of progenies that had the same parameters evaluated at the end of pregnancy (F2). The occurrence of malformations was more frequent and diversified in nicotine-exposed F2. Brain alterations, including reduced size and changes in cell proliferation and death, were seen in both generations of nicotine-exposed rats. Male and female gonads of F1 exposed rats were also affected. The F2 rats showed reduced cellular proliferation and increased cell death on the pituitary and ovaries, besides increased anogenital distance in females. The number of mast cells was not enough altered to indicate an inflammatory process in brain and gonads. We conclude that prenatal exposure to nicotine causes transgenerational alterations in the structures of pituitary-gonadal axis in rats.

Does maternal exposure to nicotine affect the oocyte quality and reproductive capacity in adult offspring?

Gonadal development begins in the intrauterine phase and females from most species are born with an established oocyte reserve. Exposure to drugs during gestation can compromise the offspring health, also affecting the gametes quality. Nicotine, the main component of cigarettes, is an oxidant agent capable of altering the fertility in men and women. As female gametes are susceptible to oxidative stress, this drug can damage the oolemma and affect oocyte maturation, induce errors during chromosomal segregation and DNA fragmentation. Oocyte mitochondria are particularly susceptible to injuries, contributing to the oocyte quality loss and embryonic development disruption. Thus, considering the high number of women who smoke during pregnancy, while significant events are occurring in the embryo for future fertility of offspring, we seek to verify the quality of the oocytes from adult rats exposed to nicotine during intrauterine phase and breastfeeding. Pregnant Wistar rats received nicotine by osmotic mini-pumps and the female progenies were evaluated in adulthood for oocyte quality (viability, lipid peroxidation, generation of reactive oxygen species and mitochondrial integrity) and reproductive capacity. Embryos (3dpc) and fetuses (20dpc) generated by these rats were also evaluated. The results showed that the dose of 2 mg/kg/day of nicotine through placenta and breast milk does not affect the number of oocytes and the fertility capacity of adult rats. However, it causes some morphological alterations in oocytes, mitochondrial changes, embryonic fragmentation and disruption of fetal development. The malformations in fetuses generated from these gametes can also indicate the occurrence of epigenetic modifications.

Carnitine partially improves oxidative stress, acrosome integrity, and reproductive competence in doxorubicin-treated rats.

Doxorubicin has been largely used in anticancer therapy in adults, adolescents, and children. The efficacy of l-carnitine as an antioxidant substance has been confirmed both in humans and rats. Carnitine, present in testis and epididymis, is involved in sperm maturation. It is also effective in infertility treatment. As a continuation of a previous study, we evaluated whether some spermatic qualitative parameters, DNA integrity, chromatin structure, and fertility status, could be ameliorated by the carnitine treatment in adult rats, which were subsequently exposed to doxorubicin at pre-puberty. Pre-pubertal male rats were distributed into four groups: Sham Control; Doxorubicin; l-carnitine; l-carnitine + Doxorubicin (l-carnitine injected 1 h before doxorubicin). At 100 days of age, all groups were reassigned into two sets: One set was submitted to the evaluation of sperm motility, acrosome integrity, mitochondrial activity, sperm chromatin structure analysis (SCSA), and evaluation of the oxidative stress. The other set of rats was destined to the evaluation of reproductive competence. The percentage of spermatozoa with intact acrosome integrity was higher in the Carnitine+Doxorubicin group when compared with the Doxorubicin group. However, sperm motility and mitochondrial activity were not improved by carnitine pre-treatment. Both values of malondialdehyde and nitrite (indirect measurement of nitric oxide) concentrations were statistically higher in the only doxorubicin-treated group when compared to the Carnitine + Doxorubicin group. Fertility index and implantation rate were lower in Doxorubicin group, when compared to Carnitine + Doxorubicin group. Moreover, the percentage of spermatozoa with damaged DNA was higher in the Doxorubicin-treated group when compared to the Carnitine+Doxorubicin group. l-carnitine, when administered before doxorubicin, partially preserved the acrosome integrity, an important feature related to sperm fertilization ability that positively correlated with the reproductive competence and sperm DNA integrity at adulthood. In conclusion, l-carnitine attenuated the long-term alterations caused by doxorubicin in the germ cells and improved male reproductive capacity in adulthood.

Late reproductive analysis in rat male offspring exposed to nicotine during pregnancy and lactation.

We previously observed that nicotine, administered to rats (Wistar) during pregnancy and lactation periods, provokes, in the progeny, late morphofunctional alterations in Leydig cell, body weight increase in adulthood (90 days post partum, dpp) as well as seminiferous epithelium injury. Aiming to investigate whether the spermatogenic damage previously observed in adult progenies from pregnant and lactating nicotine-exposed rat dams are maintained or whether it is worsened in older rats, we analyzed the morphological testicular alterations after up to two complete periods of spermatogenesis (53 days each), spermatic parameters, and sperm DNA fragmentation. Pregnant and lactating rats were nicotine-exposed (2 mg/kg/day) through an osmotic minipump implanted on the first day of pregnancy and replaced after birth. Absolute Control (no minipump) and Sham Control (minipump without nicotine) groups were established. The offspring were killed at 90, 143, and 196 dpp. Significant alterations in morphometric and stereological testicular parameters, such as concentration of sperm number, daily sperm production, and plasma and intratesticular levels of cholesterol and testosterone were not observed in nicotine-exposed rats. Testicular histopathological analysis showed small intraepithelial vacuolization and an accentuated germ cell desquamation in exposed rats. However, the offspring from nicotine-exposed dams exhibited higher frequency of morphologically abnormal spermatozoa and lower sperm motility in comparison with control groups. In addition, nicotine-exposed groups showed a significant reduction in sperm mitochondrial activity and an increased sperm DNA fragmentation (Comet assay). These results indicate a late reproductive damage in the male progeny caused by maternal nicotine exposure, related to the decrease in sperm quality.

Prenatal and lactation nicotine exposure affects Sertoli cell and gonadotropin levels in rats.

Nicotine is largely consumed in the world as a component of cigarettes. It can cross the placenta and reach the milk of smoking mothers. This drug induces apoptosis, affects sex hormone secretion, and leads to male infertility. To investigate the exposure to nicotine during the whole intrauterine and lactation phases in Sertoli cells, pregnant rats received nicotine (2 mg/kg per day) through osmotic minipumps. Male offsprings (30, 60, and 90 days old) had blood collected for hormonal analysis (FSH and LH) and their testes submitted for histophatological study, analysis of the frequency of the stages of seminiferous epithelium cycle, immunolabeling of apoptotic epithelial cells (TUNEL and Fas/FasL), analysis of the function and structure of Sertoli cells (respectively using transferrin and vimentin immunolabeling), and analysis of Sertoli-germ cell junctional molecule (ß-catenin immunolabeling). The exposure to nicotine increased the FSH and LH plasmatic levels in adult rats. Although nicotine had not changed the number of apoptotic cells, neither in Fas nor FasL expression, it provoked an intense sloughing of epithelial cells and also altered the frequency of some stages of the seminiferous epithelium cycle. Transferrin and ß-catenin expressions were not changed, but vimentin was significantly reduced in the early stages of the seminiferous cycle of the nicotine-exposed adult rats. Thus, we concluded that nicotine exposure during all gestational and lactation periods affects the structure of Sertoli cells by events causing intense germ cell sloughing observed in the tubular lumen and can compromise the fertility of the offspring.

Carnitine partially protects the rat testis against the late damage produced by doxorubicin administered during pre-puberty.

Doxorubicin, an anticancer drug, is widely included in chemotherapy protocols to combat childhood cancer. Carnitine, an important quaternary amine, is present in testis and epididymis and is involved in sperm maturation; it has been used in infertility treatment. In a previous study, our group observed that L-carnitine given before etoposide, another chemotherapeutic drug, reduces the spermatogenic damage and protects germ cells against apoptosis. This study aimed to evaluate the antiapoptotic and cytoprotective actions of L-carnitine in long- and mid-term basis, on the seminiferous epithelium of doxorubicin-treated pre-pubertal rats. Forty-eight 30-day-old male Wistar rats were distributed into four groups: sham-control; doxorubicin; carnitine; carnitine/doxorubicin (L-carnitine injected 1 h before doxorubicin). The rats were submitted to euthanasia at 64 and 100 days of age and their testes were collected for biometric, morphometric, and histopathological analyses. The numerical density of apoptotic germ cells was obtained (TUNEL method). In adult phase (100 days), the following spermatic parameters were analyzed: mature spermatid (19 step) count and sperm daily production per testis; sperm number and transit time through the epididymal caput/corpus and cauda; frequency of morphologically abnormal spermatozoa (from epididymal fluid), as well as sperm DNA integrity (Comet assay). The testicular and spermatic parameters at both ages were improved in rats treated with carnitine before doxorubicin. At 64 days, the TUNEL-positive germ cell frequency was lower in the carnitine/doxorubicin-treated rats comparatively to the doxorubicin-treated rats. At 100 days of age, the sperm DNA fragmentation was also lower in the previously carnitine-treated rats, as evidenced by the analysis of three parameters. Carnitine reduced the late testicular and spermatic damages caused by doxorubicin, probably providing a partial cytoprotection against the deleterious action of doxorubicin administration to pre-pubertal rats. However, further studies shall be undertaken to investigate the protective mechanisms involved in such germ cell preservation.

Effects of prenatal and lactation nicotine exposure on rat testicular interstitial tissue.

Nicotine is largely consumed as a component of cigarettes. It induces apoptosis, interferes with endocrine function by changing the sex hormones secretion and leads to male infertility. Testosterone is produced from cholesterol by Leydig cells (LC), with the participation of testicular macrophages (MO). Thus, to investigate whether nicotine administration to pregnant and lactating rats changes cholesterol and sexual hormone levels and LC and MO populations of offspring, female rats received nicotine (2 mg/kg/day) through osmotic minipumps from the first day of pregnancy up to the end of weaning. At 1, 30, 60 and 90 days post-partum (dpp) the plasma cholesterol and testosterone levels were obtained, as well as the biometric, histopathological and stereological testicular parameters. Nicotine reduced the body weight, cholesterol levels and lipid droplet number in foetal LC at 1 dpp. The number of apoptotic LC did not change in the offspring of nicotine group at any age studied. No alterations in the numerical densities of MO and LC occurred at 60 and 90 dpp. Hypertrophy of mature LC and increase in cholesterol and testosterone levels were noted at 90 dpp. In conclusion, nicotine when administered to rats throughout pregnancy and lactation induces morphofunctional alterations of foetal and mature LC and affects cholesterol and testosterone levels.

Reproductive function of the male obese Zucker rats: alteration in sperm production and sperm DNA damage.

Obesity has been considered a public health issue in many countries and is of increasing concern for authorities over the past 6 years. The Zucker rat is a good experimental model for obesity and diabetes studies due to its metabolic characteristics that are similar to those developed by humans. A total of 12 obese Zucker rats and their lean littermates were killed in pubertal and young adult phases for assessing organ weights (testis and epididymis), testicular histomorphometric and stereological analyses, daily sperm production, and transit time in the epididymis. Sperm integrity was also investigated in the adult animals using the Comet assay. Alterations in organ weights, seminiferous epithelium architecture, sperm production, and transit time were noticed in the pubertal fatty rats. The volume density of the lymphatic space was decreased in both the ages. Adult animals had a significant increase in the extent of damage found in sperm DNA. Our results show for the first time that leptin receptor deficiency compromises sperm production during puberty and that genetic obese Zucker rats have increased sperm DNA fragmentation.

Amifostine-doxorubicin association causes long-term prepubertal spermatogonia DNA damage and early developmental arrest.

BACKGROUND: In a previous study, we found that amifostine provides some protection to the seminiferous epithelium of prepubertal doxorubicin-treated male rats but does not improve their fertility status as adults. Based on these results, a long-term study was undertaken to evaluate the DNA damage caused to spermatogonia and the consequences for embryo development. METHODS: Twenty-four male prepubertal rats (30-day-old) were divided into four equal groups and treated with: doxorubicin (D--5 mg/kg), amifostine (A--400 mg/kg), amifostine/doxorubicin (AD--amifostine 15 min before doxorubicin) and control (C--0.9% saline solution). Sixty-four days after the treatment, animals were euthanized and the testes and epididymides were excised. The testes were fixed in Bouin's solution and historesin-embedded for histopathological analysis. Spermatozoa from the cauda epididymides were collected for chromatin structure analyses (Comet Assay and SCSA™). Adult rats (100-day-old) were mated with fertile females for embryo analyses on 2.5, 4.5 and 20 days post-coitum (d.p.c.). RESULTS: The seminiferous epithelium histopathology of AD group was better preserved compared with the D group. On the other hand, rats from the D and AD groups presented an increased percentage of sperm DNA strand breaks, as assessed by the comet assay, as well as an increased level of sperm chromatin denaturation, as assessed by the SCSA™ assay. In amifostine-treated groups (A and AD) there was a significant increase in the number of arrested embryos, as observed by the number of oocytes/zygotes on 2.5 d.p.c., when compared with control and doxorubicin groups; however, this number was increased when the AD group was compared with the A group. CONCLUSIONS: These results raise a concern about the effects of the association of these two drugs on the germ cell genome. Amifostine-doxorubicin-exposed rat spermatogonia produced long-term damage on sperm DNA, compromised conceptus development and reduced pregnancy outcome.

Testosterone-immunopositive primordial germ cells in the testis of the bullfrog, Rana catesbeiana.

In amphibia, steroidogenesis remains quiescent in distinct seasonal periods, but the mechanism by which spermatogenesis is maintained under low steroidogenic conditions is not clear. In the present study, testosterone location in the testes of Rana catesbeiana was investigated immunohistochemically during breeding (summer) and nonbreeding (winter) periods. In winter, the scarce interstitial tissue exhibited occasional testosterone immunopositivity in the interstitial cells but the cytoplasm of primordial germ cells (PG cells) was clearly immunopositive. By contrast, in summer, PG cells contained little or no immunoreactivity whereas strong immunolabelling was present in the well-developed interstitial tissue. These results suggest that PG cells could retain testosterone during winter. This androgen reservoir could be involved in the control of early spermatogenesis in winter and/or to guarantee spermiogenesis and spermiation in the next spring/summer. The weak or negative immunoreaction in the summer PG cells might reflect consumption of androgen reservoir by the intense spermatogenic activity from spring to summer. Thus, besides acting as stem cells, PG cells of R. catesbeiana could exert an androgen regulatory role during seasonal spermatogenesis.

In situ demonstration of both TUNEL-labeled germ cell and Sertoli cell in the cimetidine-treated rats.

Cimetidine has caused dysfunction in the male reproductive system. In the rat testis, intratubular alterations and loss of peritubular tissue due to peritubular myoid cell death by apoptosis have been recently shown. Thus, the aim of this study is to evaluate which cells of the seminiferous epithelium have been affected and/or died by apoptosis after the treatment with cimetidine. For this purpose, an experimental group containing five male albino Wistar rats received intraperitoneal injections of cimetidine (50 mg/kg body weight) during 52 days. The testes were fixed with 4% buffered formaldehyde and were embedded in paraffin. For detection of DNA breaks (apoptosis) in the cells of the seminiferous epithelium, the testicular sections were treated by the TUNEL method (Apop-Tag Plus Peroxidase Kit). In the tubules affected by cimetidine, altered peritubular tissue, including the presence of TUNEL labeling in the myoid peritubular cells, were usually found. In these tubules, the seminiferous epithelium exhibited low density of germ cells and TUNEL-positive labeling in the germ cells of the basal compartment. The concomitant staining in both germ cells of the basal compartment and late spermatids suggest a sensitivity of these cells in the damaged tubules. Besides germ cells, TUNEL-positive Sertoli cells were also found in the injured seminiferous tubules. Thus, a relationship between dying germ cells and Sertoli cell damage and/or death must be considered in tubules where peritubular tissue has been affected by toxicants.

Intrauterine food restriction as a determinant of nephrosclerosis.

We previously showed that 3-month-old rats subjected to a 50% intrauterine food restriction had a decreased number of nephrons with increased glomerular diameter, which suggests compensatory hypertrophy. Hypertrophy could be the early event of glomerular damage. In this study, we extended our investigation and performed functional, morphological, and immunohistochemical evaluations in 3- and 18-month-old rats that underwent a 50% intrauterine food restriction (RT3 and RT18, respectively) and age-matched control rats (C3 and C18, respectively). Our findings showed that glomerular filtration rate was significant decreased in RT18 rats (2.42 +/- 0.15 mL/min/kg; n = 28; P: < 0.05) compared with C18 control rats (4.19 +/- 0.10 mL/min/kg; P: < 0.05) and the percentage of glomeruli with sclerosis was greater in RT18 rats (13.01% +/- 2.95%; n = 9; P: < 0.01) than in C18 rats (2.71% +/- 0.35%; n = 6). RT18 rats also showed more intense tubulointerstitial lesions and immunohistochemical alterations in the renal cortex. Immunohistochemical studies showed increased fibronectin and desmin expression in glomeruli and tubulointerstitium and increased vimentin and alpha-smooth muscle actin in the tubulointerstitial area from the renal cortex of RT18 rats (P: < 0.05). Desmin was also increased at the edge of glomeruli from RT18 rats, suggesting podocyte injury. Our data show that when food restriction is imposed during pregnancy, permanent damage occurs in the kidney of the offspring. Glomerular lesions were more severe than the tubulointerstitial damage in these animals.

Morphological alterations and intratubular lipid inclusions as indicative of spermatogenic damage in cimetidine-treated rats.

Doses of cimetidine (50 mg/kg b/w) were administered to adult male Wistar rats over 52 consecutive days. Besides plasma testosterone levels, morphological and morphometric aspects of the seminiferous tubules as well as histochemical analysis of the lipid content by oil red O were emphasized. Abnormal tubules exhibiting disorganization of their cellular association, loss of germ cells, and multinucleated giant spermatids were usually found. Significant reductions of testis weight and tubular diameter at specific stages (VII-IX), as well as lack of contact between Sertoli cells and spermatids in tubules at stage IX, suggest a possible interference of cimetidine on the histoarchitecture of the seminiferous epithelium. The dense concentration of lipid inclusions in tubules at postspermiation stages indicates phagocytosis and degradation of germ cells. Since no change in serum testosterone levels was verified in cimetidine-treated rats, the authors could not exclude the possibility that besides an antiandrogenic effect, other biochemical factors necessary for normal spermatogenesis could be involved in the testicular alterations.

Functional and morphometric evaluation of offspring kidney after intrauterine undernutrition.

Pregnant rats were subjected to 50% food restriction during the first or the second half of pregnancy, or throughout pregnancy. The effects of intrauterine food restriction, on kidney function and morphometry were studied in newborn and adult (3 months) offspring. No differences in glomerular diameter were observed in newborn restricted rats compared with controls. The number of glomeruli was significantly lower both in newborn and 3-month-old restricted rats. However, glomerular diameter was increased in 3-month-old rats, which suggests that hypertrophic stimuli were present. The medulla/cortex ratio increased in adult rats submitted to food restriction during pregnancy, a finding that agrees with the preserved sodium and acid excretion, and the normal osmolar and free water clearance observed in these groups. These results show that the reduction in glomerular number is still present 3 months after birth in the progeny of mothers submitted to severe food restriction during pregnancy, suggesting impairment of glomerulogenesis even after birth. Intra utero undernutrition can be regarded as an experimental model of glomerular hypertrophy.

Histomorphometry of immature rat testis after heating.

The scrotal testes of albino rats aged 35 and 45 days were immersed in water at constant temperatures of 43 degrees C, 44 degrees C, or 45 degrees C for periods of 15-45 min in a special heating device. At an age of 60 days, the rats were mated in individual cages with two primiparous rats each. At an age of 90 days, they were killed and their testes were histologically processed. Rats with testes that had been subjected to heating when the animals were 45 days old showed both alterations of the seminiferous tubules and a decrease in fertilizing capacity. The effect of heat was greater in animals at 45 than at 35 days of age. In heat-treated testes, tubules contained PAS-positive concretion, sometimes engulfed by macrophage-derived giant cells and multinucleate cells derived from spermatids that failed to separate during spermiogenesis. The decrease in testicular volume observed after heat treatment was due mainly to reduced parenchymal volume. Thermic lability of seminiferous stem cells increases with age until adulthood, and recovery from heat injury declines.

Function and morphometric evaluation of intrauterine undernutrition on kidney development of the progeny

Renal function and renal morphometry of the progeny of rats submitted to 50% dietary restriction (pairfed with control group) throughout pregnancy (Rtgroup), during the first half of pregnancy (R1 group) or during the second half of pregnancy (R2 group) were studied 3 months after birth. Glomerular filtration rate (GFR) and renal plasma flow (RPF) decrease significantly in all groups when compared to control (C) (GFR, 4.44 ñ 0.12, 4.04 ñ 0.18, and 4.00 ñ 0.16 vs 6.87 ñ 0.17, and RPF, 19.06 ñ0.57, 17.00 ñ 1.14, and 13.31 ñ0.50 vs 22.57 ñ 0.67, respectively). Urinary osmolality tended to be lower in the R2 and Rt groups (887.1 ñ 42.36 and 868.0 ñ 42.36 vs 975.1 ñ 38.31 in C), and the net acid excretion calculated per ml of GFR was either maintained or stimulated (R1 group). A significant decline in the number of glomeruli occurred in R1, R2 and Rt rats (79.84 ñ 2.08, 62.30 ñ 2.07, and 58.16 ñ 2.32 vs 99.77 ñ 2.28 in C repectively). The results show that intrauterine undernutrition actually caused a deleterious effect on the number of functional nephrons

Function and morphometric evaluation of intrauterine undernutrition on kidney development of the progeny.

Renal function and renal morphometry of the progeny of rats submitted to 50% dietary restriction (pair-fed with control group) throughout pregnancy (RT group), during the first half of pregnancy (R1 group) or during the second half of pregnancy (R2 group) were studied 3 months after birth. Glomerular filtration rate (GFR) and renal plasma flow (RPF) decreased significantly in all groups when compared to control (C) (GFR, 4.44 +/- 0.12, 4.04 +/- 0.18, and 4.00 +/- 0.16 vs 6.87 +/- 0.17, and RPF, 19.06 +/- 0.57, 17.00 +/- 1.14, and 13.31 +/- 0.50 vs 22.57 +/- 0.67, respectively). Urinary osmolality tended to be lower in the R2 and RT groups (877.1 +/- 42.36 and 868.0 +/- 42.36 vs 975.1 +/- 38.31 in C), and the net acid excretion calculated per ml of GFR was either maintained or stimulated (R1 group). A significant decline in the number of glomeruli occurred in R1, R2 and RT rats (79.84 +/- 2.08, 62.30 +/- 2.07, and 58.16 +/- 2.31 vs 99.77 +/- 2.28 in C respectively). The results show that intrauterine undernutrition actually caused a deleterious effect on the number of functional nephrons.

Structural and ultrastructural alterations of epithelial cells of vas deferens caused by contrast medium

In a attempt to verify experimentally any possible alterations of epithelial cells of vas deferens caused by radiopaque substance, the right and left vasa deferential of 3 rats were injected respectively with saline solution (0.9 per cent NaCl) and Conray-400 (66.8 per cent sodium iodomethamate). 72 hours later, the animals were killed by cranial trauma and histolofical sections and electronmiucrographs of their vasa deferentia were observed. The histological sections of epithelial cells of left vasa deferentia showed a decrease in height and slight changes in stereocilia as compared with those of right contralateral vasa deferentia. Electronmicrographs displayed a reduction in number and size of stereocilia and alterations of many mitochondria in epithelial cells of left vasa deferentia

Contribuicao ao estudo das variacoes anatomicas dos giros do lobulo parietal inferior no homen. / Anatomical variations of the gyri of the inferior parietal lobule in the man

Dispondo-se de 100 cerebros de individuos adultos brasileiros estudou-se a anatomia macroscopica das variacoes dos giros supramarginal e angular, os quais compoem o lobulo parietal inferior, em funcao dos 3 fatores de variacoes: sexo, grupo etnico e simetria no lado. Justifica-se a proposicao desta investigacao em face da previcao de delimitacao das areas corticais para estudos citoarquitetonicos, pela importancia da regiao enfocada na fisiologia da linguagem humana e animal, em decorrencia da complexidade que os giros e sulcos possam apresentar, pela utilidade na orientacao, localizacao e em estudos topograficos desta area e de sua extensao