The lateral hypothalamus is involved in the pathway mediating the hypotensive response to cingulate cortex-cholinergic stimulation

1. The injection of acetylcholine (ACh) into the medial prefrontal cortex (MPFC) caused marked hypotensive response in either unanesthetized or anesthetized rats. 2. The present experiment was designed to investigate anatomical connections of the ACh injection site in the MPFC with putative autonomic-related brain nuclei, as well as their possible involvement in the mediation of the hypotensive response to ACh. 3. For the above purpose, the bidirectional neuronal tracer biotinylated dextran amine (BDA) was injected into Cg1 and Cg3 areas, within the MPFC of male Wistar rats. Five days later the animals were sacrificed and brain slices were processed and analyzed to determine neuronal projections efferent from as well afferent to the MPFC. 4. Neuronal staining was more prominent in regions ipsilateral to the BDA injection site. Prominent efferent projections of the MPFC were observed in the contralateral MPFC: ipsi- and contralateral amygdala and hypothalamus; ipsilateral septal area, diagonal band, and zona incerta. 5. Similar but not equal patterns of neuronal labeling were observed when BDA injections were performed within the two adjacent MPFC areas. BDA injections centered in the ACh injection site in the Cg3 area caused strong labeling in the septal area and diagonal band as well as an overall hypothalamic labeling. Within the hypothalamus an intense cortical projection was observed in the lateral hypothalamus (LH). BDA injections into the Cg1 area caused a more evident labeling of the amygdaloid complex. 6. Neuronal cell bodies were evident throughout the MPFC as well as in the sensory-motor cortex when BDA was injected into the LH, thus indicating a massive ipsilateral cortical projection from the Cg3 to the LH. 7. Bilateral NMDA-induced lesions within the LH caused a significant attenuation of the depressor responses to ACh injection in the MPFC, whereas unilateral lesions were marginally effective. These results indicate the involvement of the LH in the mediation of the hypotensive response to ACh injection into the MPFC as well as the bilateral distribution of the hypotensive pathway.

Effect of NMDA-induced lesion of the subfornical organ on the angiotensin II binding sites density and acetylcholinesterase or NADPH-diphorase activities in the lamina terminalis of the rat brain

1. Neural angiotensinergic circuitry located in the lamina terminalis has been proposed to be involved in blood pressure regulation and fluid homeostasis. 2. ANG II binding sites have been described to be localized throughout the lamina terminalis including the subfornical organ (SFO), the median preoptic nucleus (MnPO), and the organum vasculosum lamina terminalis (OVLT). 3. The present experiment was designed to investigate the ANG II binding sites localization in the lamina terminalis. For this purpose, we have compared the ANG II binding sites, acetylcholinesterase, and NADPH-diaphorase distributions throughout the lamina terminalis. Additionally, we have studied the effect of the preferential lesion of SFO neuronal cell bodies by local injection of NMDA on the ANG II binding sites density in different areas of the lamina terminalis. 4. Male Wistar rats were anesthetized, immobilized in a stereotaxic apparatus, and 500 nl of saline or 250 nmol NMDA was injected into the SFO. 5. Animals were sacrificed 1 week later, the brain was removed, frozen, and sagittal 16 microm slices were cut in a cryostat. Alternate brain slices were incubated with [125I]-Sar1-ANG II for receptor autoradiography or histochemically stained for visualization of acetylcholinesterase and NADPH-diaphorase activities. Binding capacity was determined by computerized quantitative densitometry of autoradiograms. The intensity of histochemical reactions was measured as relative units obtained by computerized densitometry processing of the brain slices stained for either activity. 6. Acetylcholinesterase staining was mainly located in the SFO, with faint staining reaction in other areas of the lamina terminalis. NADPH-diaphorase staining was homogeneously distributed throughout the lamina terminalis. A significant positive correlation was observed between acetylcholinesterase and NADPH-diaphorase stainings in the SFO of control and NMDA-lesioned rats. 7. ANG II binding sites were localized throughout the lamina terminalis. A significant positive correlation was observed between the density of ANG II binding sites and the intensity of acetylcholinesterase or NADPH-diaphorase staining in the SFO of control and NMDA-lesioned rats. 8. The distribution of the NADPH-diaphorase staining was found to closely match the distribution of the ANG II binding sites in the lamina terminalis. 9. Neuronal lesion of the SFO caused significant reductions in the density of ANG II biding sites in the SFO (-68%) and the MnPO (-48%). No changes were observed either in the OVLT or outside the lamina terminalis in the superior colliculus. 10. The present results indicate the following: first, the presence of high levels of acetylcholinesterase staining in the SFO and of NADPH-diaphorase throughout the lamina terminalis; second, that ANG II binding sites in the SFO and possibly in the MnPO are localized in neuronal cell bodies; third, that SFO lesion did not affect the expression of ANG II binding sites in the OVLT, thus suggesting that these binding sites correspond to different angiotensinergic system: and finally, the existence of a striking correlation between the distribution of the ANG II binding sites and NADPH-diaphorase throughout the lamina terminalis, thus suggesting a interrelation between angiotensinergic and nitrergic systems in the lamina terminalis.

Angiotensin-converting enzyme inhibition by lisinopril enhances liver regeneration in rats

Bradykinin has been reported to act as a growth factor for fibroblasts, mesangial cells and keratinocytes. Recently, we reported that bradykinin augments liver regeneration after partial hepatectomy in rats. Angiotensin-converting enzyme (ACE) is also a powerful bradykinin-degrading enzyme. We have investigated the effect of ACE inhibition by lisinopril on liver regeneration after partial hepatectomy. Adult male Wistar rats underwent 70% partial hepatectomy (PH). The animals received lisinopril at a dose of 1 mg kg body weight(-1) day(-1), or saline solution, intraperitoneally, for 5 days before hepatectomy, and daily after surgery. Four to six animals from the lisinopril and saline groups were sacrificed at 12, 24, 36, 48, 72, and 120 h after PH. Liver regeneration was evaluated by immunohistochemical staining for proliferating cell nuclear antigen using the PC-10 monoclonal antibody. The value for the lisinopril-treated group was three-fold above the corresponding control at 12 h after PH (P<0.001), remaining elevated at approximately two-fold above control values at 24, 36, 48 (P<0.001), and at 72 h (P<0.01) after PH, but values did not reach statistical difference at 120 h after PH. Plasma ACE activity measured by radioenzymatic assay was significantly higher in the saline group than in the lisinopril-treated group (P<0.001), with 81% ACE inhibition. The present study shows that plasma ACE inhibition enhances liver regeneration after PH in rats. Since it was reported that bradykinin also augments liver regeneration after PH, this may explain the liver growth stimulating effect of ACE inhibitors.

Medial prefrontal cortex acetylcholine injection-induced hypotension: the role of hindlimb vasodilation

The injection of acetylcholine (ACh) into the cingulate region of the medial prefrontal cortex (MPFC) causes a marked fall in arterial blood pressure which is not accompanied by changes in heart rate. The purpose of the present study was to investigate the hemodynamic basis for this stimulus-induced hypotension in Sprague-Dawley rats. The study was designed to determine whether a change in the vascular resistance of hindlimb, renal or mesenteric vascular beds contributes to the fall in arterial pressure in response to ACh injection into the cingulate cortex. Miniature pulsed-Doppler flow probes were used to measure changes in regional blood flow and vascular resistance. The results indicated that the hypotensive response was largely due to a consistent and marked vasodilation in the hindlimb vascular bed. On this basis, an additional experiment was then undertaken to determine the mechanisms that contribute to hindlimb vasodilation. The effect of interrupting the autonomic innervation of one leg on the hindlimb vasodilator response was tested. Unilateral transection of the lumbar sympathetic chain attenuated the cingulate ACh-induced vasodilation in the ipsilateral, but not in the contralateral hindlimb. These results suggest that the hypotensive response to cingulate cortex-ACh injection is caused by skeletal muscle vasodilation mediated by a sympathetic chain-related vasodilator system.

Cardiovascular response to the injection of acetylcholine into the anterior cingulate region of the medial prefrontal cortex of unanesthetized rats

Injection of acetylcholine (ACh) (2.5-60 nmol) into the anterior cingulate cortex caused dose-dependent hypotensive responses (Emax = -25.3 mmHg) and no change in the heart rate. The hypotensive response to 30 nmol of ACh was blocked by local pretreatment with atropine (3 nmol) or 4-DAMP (6.7 nmol), a non-tropine muscarinic antagonist. When the same dose of atropine was injected i.v., no changes were observed in the hypotensive response to intracortical ACh. This observation rules out the possible leakage of ACh into the peripheral circulation and favors the idea of a cortical site of action. The injection of the same dose of ACh into the corpus callosum or the occipital cortex did not cause changes in the cardiovascular system. The present results confirm earlier evidence that the cingulate cortex is involved in the control of the autonomic system and indicate that cholinergic muscarinic receptors in the cingulate cortex mediate a hypotensive response without a change in heart rate.

Brain sites involved in the antinociceptive effect of bradykinin in rats

The localization of brain sites where bradykinin (BK) induces its antinociceptive effect in rats, was studied using as index the threshold for the jaw-opening reflex elicited by the dental pulp electrical stimulation test (DPEST). The microinjection of BK into the lateral or fourth cerebral ventricles induced an antinociceptive effect, with Index of Antinociception (IA) of 0.51+/-0.03 and 0.68+/-0.05, respectively. However, microinjections of the peptide into the third ventricle induced a less marked antinociception (IA = 0.28+/-0.08). The brain sites where the microinjection of BK caused an antinociceptive effect were: locus coeruleus, principal nucleus, oral part of the spinal sensorial trigeminal nucleus, and the sensory root of the trigeminal nerve. The antinociceptive effect was more intense when BK (4-16 nmol) was injected into the locus coeruleus. Microinjection of BK (4 nmol) into the fourth ventricle, but not into the locus coeruleus, induced an increase in blood pressure. The microinjection of the peptide into the nucleus tractus solitarius, a site that is also involved in the pressor effect of BK, did not induce an antinociceptive effect. These results indicate that the antinociceptive effect of BK is not related to blood pressure changes. The microinjection of BK into some of the sites involved in the mechanisms of analgaesia, including the periaqueductal gray matter (dorsal, lateral and ventrolateral) and the dorsal raphe nucleus did not induce an antinociceptive effect. The results suggest that the most likely brain sites involved in the antinociceptive effect of BK are the locus coeruleus and the principal sensory trigeminal nucleus. The present results did not exclude the involvement of other brain sites surrounding the lateral and the third ventricles.

Stereotaxic atlas of the telencephalon of the weakly electric fish Gymnotus carapo

A restraining box for the head and body of the electric fish Gymnotus carapo was constructed and coupled to a micromanipulator, permitting us to prepare an atlas of the telencephalon with stereotaxic parameters. A photograph and a schematic drawing of an animal's head is presented, showing two skin electroreceptors that were used as external landmarks. A sagittal section of the telencephalic structure is also presented, whose vertical bars indicate the frontal planes that compose the atlas. The frontal planes of the atlas consist of serial sections spaced 600 or 500 microns apart in the rostrocaudal axis. Sections mapped with acetylcholinesterase are shown, intercalated with Nissl-stained sections. The acetylcholinesterase sections proved to be useful for the delimitation of certain nuclei and for the exact localization of small fissures and fiber tracts. A brief description of major cytoarchitectural subdivision and connections of the telencephalon is provided.

[American tegumentary leishmaniasis: Phlebotominae in an area of disease transmission, the city of Pedro de Toledo, southern region of the state of Sao Paulo, Brazil]

Considered as an American tegumentary leishmaniasis (ATL) endemic area, Ribeira Valley, in the south region of São Paulo State, presented 929 notified cases in the last 15 years. Aiming to identify the phlebotomine fauna, captures were performed fortnightly in the rural area of Pedro de Toledo County during one year, from may 1994 onwards. Set at dusk Shannon traps were used in the peridomicile and CDC light traps both intra and peridomiciliarly and at the edge and in the forest. Eight species summing to 11,096 specimens were caught, L. intermedia being the dominant one (96.4%). More frequent all over the year during the first half of the night preferably in the domicile surroundings this species clearly indicated its preference for the anthropic environment. The data presented in this paper ratify L. intermedia as an important ATL vector species in the Ribeira Valley.

[Observations on oviposition, hatching and the life span of Triatoma matogrossensis Leite & Barbosa, 1953 (Hemiptera, Reduviidae) as a function of their feeding on pigeons and rabbits]

A laboratory study was carried out concerning the influence of two kinds of blood-meal on egg laying, egg hatching and life span of Triatoma matogrossensis. 68 couples in 4 different groups with 20, 12, 20 and 16 individuals of each sex per group were formed. Maintained under laboratory conditions groups A1 and A2 were fed on pigeons and groups C1 and C2 were fed on rabbits. In relation to egg laying the best results were found in group A1. No differences on egg hatching were found between the groups fed on rabbits and those fed on pigeons. Concerning the life span, no differences between males and females in the 4 groups were observed but group A1 presented the longest life span and group C2 the shortest.

[American cutaneous leishmaniasis: sandflies from the transmission area in the town of Teodoro Sampaio, the southeastern region of São Paulo state, Brazil]

Sandflies were captured in a secondary forest zone in the county of Teodoro Sampaio, São Paulo, during 12 months as from May 1994. Two houses located respectively at 240 m and 850 m from the semi-deciduous forest were selected. Night Center of Disease Control trap captures were performed fortnightly from twilight to dawn intradomiciliarily, in the edge and the interior of the forest and in the peridomicile of each one of the houses. Captures were realized as well in the peridomicile using Shannon traps during 6 hour for 24 captures and 4 quarter captures from twilight to dawn. The dominant species was Lutzomyia intermedia (93.5%). A larger number of insects were captured in the traps located in the edge of the forest. In the peridomicile of both houses an equivalent number of insects were captured, although a clear predominance of males was observed in the more distant located house. In the interior of the house located near the forest a larger number of specimens predominantly female were captured. L. intermedia and L. whitmani peaks occurred in the first hour and were characteristically more abundant in May, September and December when the mean temperature varied from 21 to 25.7 degrees C and the pluviometric index as from 66.7 to 195.1 mm.

[Sandflies (Diptera, Psychodidae) from the transmission area for American cutaneous leishmaniasis in the town of Itupeva, the southeastern region of São Paulo state, Brazil]

The present study was effected aiming the verification of the seasonal, spatial and hourly of the phlebotominic species found in the county of Itupeva. Captures were performed fortnightly and 864 sand flies were collected between april/94 and march/95. 81.3% of the captured specimens belonged to 4 species: L. migonei (32.4%), L. whitmani (26.0%), L. intermedia (12.0%) e L. fischeri (10.9%). Such species showed larger densities during the cold and dry season of the year (from april to september/94) and were more active between the second and the fifth hour after twilight. L. migonei predominated almost in all the investigated surroundings being followed by L. whitmani and L. longipalpis in the domestic environments. In conclusion it is thought that in conjunction with L. intermedia, a suspect vector in the State of São Paulo, L. migonei and L. whitmani may have an important role in the transmission of cutaneous leishmaniasis in the area under study.

Alloxan diabetes reduces pleural mast cell numbers and the subsequent eosinophil influx induced by allergen in sensitized rats

Alloxan damages insulin-producing cells and has been used as an inducer of experimental diabetes in several animal species. In this study, administration of alloxan (40 mg/kg, i.v.) to rats was followed by a selective and time-dependent reduction in the number of pleural mast cells (50 +/- 2.2%, p < 0.01; mean +/- SEM), while mononuclear cell and eosinophil counts were not altered. As compared to naive rats, the reduction in mast cell numbers was first noted 48 h following alloxan administration and remained unaltered for at least 60 days. It is noteworthy, that the depletion in the mast cell population was not accompanied by alterations in the total amount of histamine stored per cell. Sensitized rats turned diabetic by alloxan treatment performed 72 h before challenge showed a less pronounced antigen-induced mast cell degranulation compared to nondiabetic rats. Moreover, rats injected with alloxan 72 and 48 but not 24 h before challenge, reacted to allergenic challenge with 50% reduction in the number of eosinophils recruited to the pleural cavity within 24 h. We found that the less pronounced eosinophil accumulation did not relate to an intrinsic cell locomotor abnormality since eosinophils from diabetic rats presented similar chemotactic responses to LTB4 and PAF in vitro as compared to matching controls. Insulin (3 IU/rat) restored basal levels of mast cells and reversed the subsequent inhibition of allergen-induced pleural eosinophilia, suggesting a causative relationship between these phenomena. Treatment with insulin also significantly increased the number of mast cells in the pleural cavity of naive rats (from 637 +/- 57 to 978 +/- 79 x 10(3) cells/cavity, p < 0.001). Consistently, previous depletion of mast cells by means of local treatment with compound 48/80 significantly reduced the antigen-induced eosinophil recruitment in sensitized animals. We conclude that the reduction in the pleural mast cell population noted in alloxan-treated rats could be directly implicated in the diminished pleural eosinophil influx following allergen challenge. This hyporesponsiveness is independent of an intrinsic abnormality of cell chemotaxis, but can be imitated by local mast cell depletion.

Biologic activities of iodinated analogues of Tyr0-bradykinin and bradykinin-Ile10-Tyr11 assessed in the rat uterus and the guinea pig ileum

1. The biological activity of bradykinin (BK) and analogues containing ofr in extended N- or C-terminal portions of the molecule, as well as that of their iodinated products, was compared in isolated rat uterus and guinea pig ileum preparations. 2. BK-Tyr10 and BK-Ile10-Tyr11 were obtained by solid phase synthesis employing fmoc chemistry. 3. Iodination of BK-Ile10-Tyr11 and Tyr0-BK was performed using iodobeads, and the products were purified by reverse-phase HPLC. 4. The relative potency (RP) of noniodinated analogues in the uterus was: Tyr0-BK (1.3) = BK (1.0) > BK-Ile10-Tyr11 (0.45) > > BK-Tyr10 (0.02) and BK (1.0) > BK-Ile10-Tyr11 (0.25) = Tyr0-BK (0.22) > > > BK-Tyr10 (0.002). The RP of mono-iodo (MI) and di-iodo (DI) products was: BK (1.0) > DI-BK-Ile10-Tyr11 (0.63) = DI-Tyr0-BK (0.63) > MI-Tyr0-BK (0.46) = MI-BK-Ile10-Tyr11 (0.40). 5. The RP of noniodinated analogues in the guinea pig ileum was: BK (1.0) > MI-Tyr0-BK (0.39) > MI-BK-Ile10-Tyr11 (0.17) = DI-Tyr0-BK (0.16) = DI-BK-Ile10-Tyr11 (0.13). 6. Differences in RP of 8-10 fold for Tyr0-BK or BK-Tyr10 and 2-fold for BK-Ile10-Tyr11 were observed between the two preparations used, indicating possible receptor differences. 7. Iodination caused a reduction in the RP of the analogues in both preparations. 8. In the rat uterus, the changes in the RP of the Tyr0-BK analogues were more evident than those observed with the iodinated analogues of BK-Ile10-Tyr11, indicating that iodination causes different changes in RP, according to the localization of the Tyr in the molecule. 9. The data support the idea that iodinated analogues of BK-Ile10-Tyr11, with intact N-terminal portion, may be as useful as iodinated analogues of Tyr0-BK for the study of BK receptors.

Central alpha 1-adrenoceptors mediate the pressor response to intracerebroventricular injection of noradrenaline in unanesthetized rats

The intracerebroventricular (i.c.v.) administration of noradrenaline (NA) caused dose-dependent blood pressure increases in unanesthetized rats with an ED50 of 35 nmol. Similar pressor responses were observed after the i.c.v. injection of the more selective alpha 1-agonists ST-91, methoxamine and phenylephrine with ED50 of 60, 155 and 575 nmol, respectively. The maximal pressor response was 57 +/- 3 mmHg. No tachyphylaxis was observed when injections of 37.5 nmol of NA was i.c.v.-injected at an interval of 24 hr. No significant differences were observed in the plasma content of NA and adrenaline at the peak of the pressor response to i.c.v.-injected NA when compared to i.c.v. injections of saline. The pressor effects of NA were blocked by the i.c.v. pretreatment with prazosin or yohimbine with ID50 of 0.9 and 29 nmol, respectively. Prazosin was 32-fold more potent than yohimbine in blocking the effect of i.c.v. NA, suggesting the involvement of alpha 1-adrenoceptors in the central mediation of the pressor response to NA. Intravenous injections of 13 nmol of prazosin or 90 nmol of yohimbine did not affect the pressor response to i.c.v. NA, further indicating the central nervous system nature of the response.

Epidemiology of Chagas' heart disease

Chagas' disease is a major public health problem in Latin America. About 16 million persons are affected and 90 million others are exposed to the risk of being infected by the parasite. The knowledge of epidemiological aspects of the disease allowed to delineate the strategies for the control of the disease related with the vectorial transmission. However, these strategies have had no priority in all endemic countries. Rural-urban migration in most endemic areas carried infected individuals to urban centers increasing the problem of Chagas' disease by blood transfusion. In Brazil the control program has reached good results in the last years and in several states the vectorial transmission was controlled. More recently, hemotherapic practices are performed using screening procedures but this practice must be improved in order to eliminate the possibility of Chagas' disease transmission by another ways (congenital, accidental, oral, etc.). An adequate health care to the infected persons must be improved in order to diminish the social costs of the severe cardiopathy which has been responsible for the adults premature deaths.

Pressor effects of acetylcholine injected into the lateral septal area of conscious rats

Injections of acetylcholine (ACh) into the lateral septal area (LSA) caused blood pressure increases in unanesthetized freely moving rats. ACh was injected in the dose range of 0.1-54 nmol/500 nl using regular metal needles (200 microns o.d.). In the LSA, injections of carbachol or ACh (2.5 nmol/500 nl) were equipotent (+22 +/- 2 and +19 +/- 3 mmHg, respectively) suggesting the existence of an ACh-sensitive pressor site in the LSA. Maximum responses to ACh injected either intracerebroventricularly (i.c.v.) or into the LSA were not significantly different (+23 +/- 1 and +21 +/- 2 mmHg, respectively). However, the ED50 for the injection into the LSA (0.24 nmol) was significantly lower than that observed after i.c.v. injection (2.6 nmol), ruling out a possible leakage of ACh from the LSA and into the ventricular space. This idea is supported by data showing that the effect of the intraseptal injection of 30 nmol of ACh was blocked by pretreatment with 3 nmol of atropine either i.c.v. or into the LSA, whereas the effects of i.c.v. ACh were completely blocked by i.c.v. atropine, but only partially (42%) when atropine was injected into the LSA. The idea of the existence of an ACh-sensitive site in the LSA is further supported by the more direct observation that injections of 30 nmol/100 nl of ACh into the LSA using glass needles (50-70 microns o.d.) caused similar pressor responses. Neither the i.v. pretreatment with pentolinium or adrenalectomy affected the response to 30 nmol/500 nl of ACh injected into the LSA, ruling out the involvement of the sympathetic nervous system.(ABSTRACT TRUNCATED AT 250 WORDS)

Lack of involvement of the kallikrein-kinin system in the depressor effect of alpha-methyldopa in normotensive rats

1. We evaluated the involvement of circulating kinins in the hypotensive effect of the antihypertensive drug alpha-methyldopa (alpha-MD) in normotensive rats. 2. The alpha-MD effects were more pronounced in urethane-anesthetized rats than in unanesthetized animals. 3. Treatment with alpha-MD did not affect the circulating levels of kininogen, the bradykinin precursor. 4. Pretreatment with captopril that potentiates the depressor effects of bradykinin did not potentiate the hypotension to alpha-MD. 5. The lack of changes in kininogen levels and the failure of captopril to potentiate the depressor effects of alpha-MD rules out an involvement of the circulating kallikrein-kinin system in the response to alpha-MD.

Autoradiographic localization and characterization of angiotensin II receptor subtypes in the rat thymus

Angiotensin II (ANG II) receptors were present in the thymus of newborn rats (179 +/- 34 fmol/mg protein). In newborns, binding was predominantly localized in the trabecula, and was selectively displaced by the AT2 ligand CGP 42112A (83-85%) and to a lower extent by the AT1 antagonist losartan (15-17%), indicating a marked predominance of AT2 receptors. Angiotensin II binding was very low in the cortical and medullary areas in the thymus of newborn rats and was no longer detected in the thymus of 4- and 8-week-old rats. No detectable binding for the ACE inhibitor [125I]351A was observed in the thymus of the rat, regardless of the age studied. Our results indicate a possible role for circulating ANG II during development of the thymus with no clear correlation to lymphocyte maturation.

Induction of the c-fos proto-oncogene in the rat pineal gland during stress

To investigate the effects of stressful stimuli on pineal gland activity, male Wistar albino rats (200-250 g, 2-4 per group) were submitted to 30 min of forced immobilization or to unilateral vibrissotomy 30 min before sacrifice. In situ hybridization was performed with a 35S-labelled 50-base oligonucleotide probe complementary to nucleotides 270-319 of rat c-fos on sections containing the pineal gland. Autoradiograms were quantified using a JAVA microdensitometer. Stressful stimuli induced a significant increase in the expression of c-fos mRNA in the pineal gland (restraint = 144.3 +/- 14.4 cpm/mm2; hemivibrissotomy = 206.7 +/- 29.5 cpm/mm2) as compared to no restraint animals (30.6 +/- 5.1 cpm/mm2), animals displaying tonic-clonic seizures after an ip (64 mg/kg) injection of pentylenetetrazole (34.0 +/- 4.7 cpm/mm2), or competition (70.6 +/- 11.4 cpm/mm2) and RNAase-treated (52.7 +/- 9.1 cpm/mm2) controls. These results raise the possibility that stressful stimuli may interfere with pineal gland function.

[Natural parasitism of buffaloes in Botucatu, SP, Brazil. III. Dynamics of gastrointestinal parasitism in cows and their calves]

Gastrointestinal parasitism of 24 buffalo cows before parturition, and post-parturition, their infection and that of their respective calves during the following 30 weeks were studied. Willis, Hoffmann and whenever possible, the modified Gordon & Whitlock techniques were used for fecal examinations. Toxocara vitulorum eggs were the earliest forms encountered in calves feces, as follows: during the 1st week after birth, 58.33% of the calves were positive, and in the 4th week, 100% of these animals were positive. Eggs of Strongyloides sp were in the 1st week after birth in two of the calves and in the 5th week, all for them were positive. The next parasites to appear were the Coccidia of which oocysts were detected in the feces of two calves in the 2nd week after birth, and 58.33% of the calves were positive for these in the 3rd week, and in the 6th week, all calves shed oocysts in their feces. On the other hand, eggs of Strongyloides were the last forms to appear in calves feces. However, despite their sporadic appearance in the feces, eggs of these parasites were observed continuously from the 11th week onwards, and at this point, the percentage of positive samples began to increase to reach its peak. Relatively to adult animals, eggs of T. vitulorum were observed in the feces of 11 cows, one or twice at most; eggs of Strongyloides sp were seen only once in the feces of four buffalo cows and eggs of Strongyloides in 21 out of 24 cows. Oocysts of Coccidia were observed in 16 cows. Mechanisms of infestation of calves with these parasites are discussed.

Cryptosporidiosis among patients with acquired immunodeficiency syndrome (AIDS) in the county of São Paulo, Brazil

Stool samples of 157 patients with AIDS, living in the county of São Paulo, were submitted to several techniques in the search for Cryptosporidium sp.. Among the various techniques tested for slide preparation (direct smear, spontaneous sedimentation method, and formol-ether concentration), the latter, formol-ether concentration, offered the best results, clearly outdoing all the others. Nineteen samples out of 157 prepared by this technique, after dyeing by the Kinyoun method or by carbol fuchsin dimethyl sulfoxide, were found to be positive for Cryptosporidium sp..

Involvement of central alpha-pressor and beta-depressor adrenoceptors in the cardiovascular response to intracerebroventricular catecholamines in the rat

Microinjections of catecholamines were performed into the lateral ventricle of anesthetized and unanesthetized rats and the blood pressure effects recorded prior to or after the administration of pharmacological antagonists. Injections of 20-100 micrograms normetanephrine (alpha-agonist) produced only pressor responses in both groups of animals. Injections of 10-20 micrograms of norepinephrine (preferentially an alpha-agonist) produced mainly pressor in awake and only depressor responses in anesthetized animals, whereas injections of 10-20 micrograms of epinephrine (preferentially a beta-agonist) produced only depressor responses in both groups of animals. Intracerebroventricular pretreatment with the beta-blocker propranolol (40-100 micrograms) blocked the depressor responses to the catecholamines or even reverted them into clear pressor response. Pretreatment with the alpha-blocker phentolamine (100 micrograms) reduced the pressor effects induced by the intraventricular injection of catecholamines. The existence of central alpha-pressor and beta-depressor mechanisms mediating the blood pressure responses to the intracerebroventricular administration of catecholamines is proposed.

Plasmodium berghei-infected mice: lack of effect of meclizine and cimetidine on the development of pulmonary oedema

The involvement of histaminergic mechanisms in the pathogenesis of pulmonary oedema observed in Plasmodium berghei-infected mice was investigated. Histamine concentrations in plasma and whole blood of infected and normal mice were determined by radioenzymatic assay during the seven days of the infection. Elevated plasma and whole blood histamine levels were found at the last stages of infection (sixth day and seventh day after ip injection of parasitized erythrocytes), showing a close temporal correlation between the development of oedema and the elevation of the circulating histamine concentrations. However, the treatment of infected mice with the H1- or H2-receptor antagonists, meclizine or cimetidine, did not change the development of pulmonary oedema. The absence of effects of H1- and H2-receptor blockers on this model is a suggestive evidence that histamine does not contribute to P. berghei-induced pulmonary oedema in mice.

Central adrenergic mediation of the cardiovascular effect of intraventricular bradykinin

The lateral septal area of anaesthetized rats was perfused using a push-pull cannula and the effect of the intracerebroventricular injection of bradykinin on the release of 3H-noradrenaline from the lateral septal area studied. A significant increase in 3H-noradrenaline release concomitant to a cardiovascular response was observed after bradykinin administration, suggesting the involvement of septal noradrenergic mechanisms in the response to the peptide. Morphine, subcutaneously administered, blocked the increase in the effluent radioactivity and the cardiovascular response to bradykinin, suggesting that the bradykinin receptors in the septal area are similar to those found in the sympathetic ganglia. Intravenous injection of diphenhydramine blocked the cardiovascular response to bradykinin but not the 3H-noradrenaline release, indicating the involvement of histaminergic mechanism in a step posterior to the release of catecholamines in the septal area.

Mechanism of the CNS-mediated pressor response to intracerebroventricular injection of noradrenaline in unanaesthetized rats

Catecholamines administered intracerebroventricularly (i.c.v.) have cardiovascular effects mediated by the CNS. Although hypotension constitutes the more prominent response, an increase in blood pressure has also been reported after the intracerebroventricular injection of these amines. Anaesthesia interferes with pressor responses mediated by the CNS to a larger extent than with depressor mechanisms and constitutes one of the major factors influencing the pattern of response to the amines. The depressor response observed after the intracerebroventricular administration of noradrenaline is reversed into increases in blood pressure in awake animals. In the present experiment, the action of intracerebroventricularly injected noradrenaline was compared in anaesthetized and conscious rats. The results indicated that the pressor response in awake rats was not mediated by the sympathetic nervous system and involved the release of a pituitary humoral-factor, most probably vasopressin, whereas the depressor response observed in anaesthetized animals was not dependent on pituitary mediation. The involvement of histaminergic mechanisms in the CNS in the control of the pressor response to intracerebroventricularly administered noradrenaline in the rat is proposed.

Central mechanisms of the isoprenaline-induced hypotension in anesthetized and conscious rats

Isoprenaline was microinjected into the cerebroventricular spaces of anesthetized or unanesthetized rats and the blood pressor effects recorded prior to or after intraventricular administration of pharmacologic antagonists. Injection of 1-20 micrograms of isoprenaline produced only depressor responses in both groups of animals. Pretreatment with 400-200 micrograms of propranolol partially antagonized the depressor effect of isoprenaline, whereas pretreatment with 40 micrograms of phenoxybenzamine or 100 micrograms phentolamine potentiated the depressor response to isoprenaline. The involvement of central beta-adrenoceptors and a propranolol-insensitive mechanism in the depressor response to intracerebroventricular isoprenaline is proposed. Indirect evidence of a central alpha-adrenoceptor mediation of pressor mechanisms counteracting the depressor responses elicited by beta-adrenoceptor stimulation is presented.

Fluorescent probes of alpha- and beta-adrenergic and opiate receptors: biochemical and histochemical evaluation

Dansyl derivatives of the opiate antagonist naloxazone and the alpha-adrenergic blocking drug 2-[2',6'-dimethoxy)phenoxyethylamino]methyl-benzodioxan (WB-4101) were synthesized as potential in vivo fluorescent labels for opiate and alpha-adrenergic receptors, respectively. When assayed in vitro dansyl analogs display Ki-values for [3H]naloxone and [3H]WB-4101 binding of 8 nM and 80 nM, respectively. The same patterns of histofluorescence are observed in rat brain slices after the intravenous or intracerebroventricular injection of both dansyl drugs. The same patterns are also observed in dansyl-propranolol and 9-aminoacridine-propranolol (9-AAPN) treated animals as well as in untreated control rats. Accordingly, the observed fluorescence does not reflect the labeling of any receptor but is consistent with the distribution of lipofuscin, an endogenous fluorescent compound.

Bradykinin-like immunoreactive neuronal systems localized histochemically in rat brain

Bradykinin-like immunoreactive structures were localized in rat brain by the indirect immunofluorescence method. Specificity of staining was demonstrated by: (i) the absence of fluorescence when preimmune serum was used, (ii) the disappearance of fluorescence when sera were preadsorbed with bradykinin, and (iii) the presence of identical staining with two different antisera. Immunoreactive neuronal cells are observed only in the hypothalamus, with especially dense clusters overlying the periventricular and dorsomedial nuclei. Fibers and varicose processes are observed in the periaqueductal gray matter, hypothalamus, perirhinal and cingulate cortices, the ventral portion of caudate-putamen, and the lateral septal area.

Cholecystokinin octapeptide-like immunoreactivity: histochemical localization in rat brain

Cholecystokinin octapeptide-like (CCK-OP-like) immunoreactivity was localized in the rat brain by using the indirect immunofluorescence method. Specificity in immunohistochemical studies was demonstrated by the virtual elimination of staining with either preimmune sera or sera preadsorbed with CCK-OP and by the achievement of similar fluorescent patterns with two different primary anti-CCK-OP sera. CCK-OP-like fluorescence was localized in neuronal cell bodies, fibers, and varicose terminals. The most dense collections of CCK-OP cells occurred in the periaqueductal gray and in the dorsomedial hypothalamus. Substantial numbers of cells and fibers also were present in the medial/dorsal and perirhinal cortex; more limited groups of cells were found in the pyramidal layer of the hippocampus and in the dorsal raphe.

Central and peripheral antialgesic action of aspirin-like drugs

The peripheral and central effects of some non-steroid anti-inflammatory drugs, aspirin, indomethacin, paracetamol and phenacetin were studied by comparing their intraplantar and intracerebroventricular effects on hyperalgesia induced by carrageenin injected into the rat paw. Hyperalgesia was measured by a modification of the Randall-Selitto test. The agents tested had antialgesic effects when given by any route. Their intraventricular administration enhanced the antialgesic effect of anti-inflammatory drugs administered into the paw. Previous treatment of one paw with carrageenin reduced the oedema caused by a second injection of carrageenin in the contralateral paw. In contrast, it had no effect on the intensity of hyperalgesia but shortened the time necessary for it to reach a plateau. Administration of a prostaglandin antagonist (SC-19220) in the cerebral ventricles, in the rat paw or in both sites, significantly inhibited the hyperalgesia evoked by carrageenin. The maximal hyperalgesic effect of intraplantar injections of prostaglandin E2 could be further enhanced by its cerebroventricular administration. It was suggested that carrageenin hyperalgesia has a peripheral and a central component and that the cyclo-oxygenase inhibitors used may exert an antialgesic effect by preventing the hyperalgesia induced by a peripheral and/or central release of prostaglandins.

[Toxoplasma gondii: indirect immunofluorescence diagnosis in swine in the State of São Paulo, Brazil]

The frequency of anti-Toxoplasma antibodies in apparently healthy swine from Botucatu and from São Paulo industrial abattoir was assessed through the indirect immunofluorescence test using blood smears collected in filter paper. 225 (22.5%) of the 1000 samples examined were reagent with titles varying between 1:20 and 1:640.

Central site of the hypertensive action of bradykinin

The intraventricular injection of 1 mug of bradykinin (BK) in rats anesthetized with urethane (1.5 g/kg i.p.) caused an increase in mean arterial blood pressure with little or no change in pulse pressure or heart rate. A similar hypertensive response followed the local administration of 0.5 mug of BK at the pars ventralis of the lateral septal area, whereas local application at other subcortical regions, known to be involved in cardiovascular regulation, caused no effect. Injections of 0.5 or 1 mug of synthetic substance P or 1 mug of 9-desarginine-bradykinin at the pars ventralis of the lateral septal area caused no change in blood pressure. In addition, bilateral electrolytical lesions placed in the lateral septal area either markedly reduced or completely blocked the pressor response to intraventricular BK. These results suggest that the pars ventralis of the lateral septal area is involved in the pressor action of BK in the central nervous system. They also indicate that this brain region responds fairly specifically to BK and that local vascular changes are unlikely to be involved in the mediation of the central action of BK.

[Prevalence of enteroparasitic diseases among the urban population of the 2nd subdistrict of Botucatu]

Procurou-se conhecer a prevalência de enteroparasitoses na população urbana do 2.° subdistrito de Botucatu, SP (Brasil) através de exames coprológicos realizados pelos métodos de FAUST, HOFFMAN e processo de tamização. A prevalência de enteroparasitoses foi relacionada com atributos da população, tais como sexo, idade, cor e com fatores ligados ao meio ambiente. O processo de amostragem empregado foi o casual simples em duplo estágio, sendo o quarteirão a unidade primária do primeiro estágio e o domicílio a unidade do segundo estágio. Os resultados mostraram que 53,76% das 895 pessoas amostradas apresentavam-se infestadas por uma ou mais espécies de parasitas intestinais. As prevalências foram as seguintes: Ancylostomidae, 17,54%; T. trichiurus, 13,63%; A. lumbricoides, 10,69%; S. stercoralis, 6,03%; E. vermicularis, 3,69%; H. nana, 1,79%; Taenia sp, 1,22%; S. mansoni, 0,22%; E. coli, 15,53%; G. lamblia, 14,07%; E. nana, 2,35%; I. bütschlii, 1,01% e E. histolytica, 0,22%.

[Parasitological survey at CECAP, Botucatu County, São Paulo State, Brazil]

Estudo da prevalência de parasitas intestinais realizado em 370 indivíduos residentes na CECAP, distrito-sede de Botucatu, Estado de São Paulo, permitiu verificar que 41,62% encontravam-se infestados por uma ou mais espécies de parasitas intestinais. Foram encontrados os seguintes parasitas: Entamoeba histolytica 0,54%, E. coli 6,21%, I. butschlii 0,27%, Giardia lamblia 9,72%, Ancylostomidae 5,94%, Strongyloides stercoralis 6,75%, Trichuris trichiura 17,29%, Ascaris lumbricoides 7,56%, Enterobius vermicularis 3,78%, Hymenolepis nana 5,40% e Taenia sp. 1,62%. Apresentam-se dados sobre a distribuição dos parasitas em relação à idade e ao sexo dos indivíduos. O atributo cor não permite maiores considerações por serem os não brancos significantemente pouco numerosos. Dos indivíduos examinados, 25,67% apresentavam apenas uma espécie de parasita e entre as associações parasitárias mais freqüentes encontramos as de Ascaris lumbricoides - Trichuris trichiura e Trichuris trichiura - Giardia lamblia.