Phenotyping of Passiflora edulis, P. setacea, and their hybrids by a multivariate approach

Morphological characterization is the most accessible and used method to quantify the genetic diversity of the available germplasm. The multivariate statistical method is highly important for this purpose. This study aimed to characterize parents and hybrids of Passiflora according to morphoagronomic descriptors and estimate the genetic divergence between them based on the joint analysis of qualitative and quantitative variables using the Ward-modified location model (MLM) procedure. One hundred and thirty-eight individuals were assessed (10 P. edulis, 10 P. setacea, and 118 interspecific hybrids) using 23 quantitative and 12 qualitative descriptors. The values for the quantitative descriptors were measured and subjected to multivariate statistics using the Ward-MLM strategy. Large genetic variability was detected by the morphoagronomic data in the 138 genotypes that were evaluated, and the hybrids presented higher variability than the parents. Pseudo-F and pseudo-t2 criteria showed that the optimal number of groups was three. Group I was composed of 118 hybrid genotypes; group II was composed of the 10 P. setacea genotypes, and group III was composed of the 10 P. edulis genotypes. The longest distance was found between groups II and III (474.96). The shortest distance was detected between groups I and II (198.78), which indicates that the segregating population is genetically closer to P. setacea than to P. edulis. The Ward-MLM procedure is a useful tool to detect genetic diversity and group accessions using both qualitative and quantitative variables.

Role of the bed nucleus of the stria terminalis in the cardiovascular responses to acute restraint stress in rats

The aim of this work was to test the hypothesis that the bed nucleus of the stria terminalis (BST) and noradrenergic neurotransmission therein mediate cardiovascular responses to acute restraint stress in rats. Bilateral microinjection of the non-specific synaptic blocker CoCl(2) (0.1 nmol/100 nl) into the BST enhanced the heart rate (HR) increase associated with acute restraint without affecting the blood pressure increase, indicating that synapses within the BST influence restraint-evoked HR changes. BST pretreatment with the selective alpha(1)-adrenoceptor antagonist WB4101 (15 nmol/100 nl) caused similar effects to cobalt, indicating that local noradrenergic neurotransmission mediates the BST inhibitory influence on restraint-related HR responses. BST treatment with equimolar doses of the alpha(2)-adrenoceptor antagonist RX821002 or the beta-adrenoceptor antagonist propranolol did not affect restraint-related cardiovascular responses, reinforcing the inference that alpha(1)-adrenoceptors mediate the BST-related inhibitory influence on HR responses. Microinjection of WB4101 into the BST of rats pretreated intravenously with the anticholinergic drug homatropine methyl bromide (0.2 mg/kg) did not affect restraint-related cardiovascular responses, indicating that the inhibitory influence of the BST on the restraint-evoked HR increase could be related to an increase in parasympathetic activity. Thus, our results suggest an inhibitory influence of the BST on the HR increase evoked by restraint stress, and that this is mediated by local alpha(1)-adrenoceptors. The results also indicate that such an inhibitory influence is a result of parasympathetic activation.

Cardiovascular effects of l-glutamate microinjection in the supraoptic nucleus of unanaesthetized rats

We report on the cardiovascular effects of L-glutamate (L-glu) microinjection in the hypothalamic supraoptic nucleus (SON) as well as possible receptor and mechanisms involved. Microinjection of L-glu in 100 nL in the SON caused dose-related pressor and bradycardic responses in unanesthetized rats. Responses were markedly reduced in urethane-anesthetized rats. The response to L-glu 10 nmol was blocked by local pretreatment with 2 nmol of the non-NMDA-receptors antagonist NBQX and not affected by 2 nmol of the selective NMDA-receptor antagonist LY 235959, suggesting that non-NMDA receptors mediate these responses. The pressor and bradycardic response to L-glu was potentiated by intravenous pretreatment with the ganglion blocker pentolinium and was blocked by intravenous pretreatment with the V1-vasopressin receptor antagonist dTyr(CH2)5(Me)AVP, suggesting involvement of circulating vasopressin in this response. Additionally L-glu microinjection into the SON increased plasma vasopressin levels (control: 1.3 +/- 0.2 pg/mL, n = 6; L-glu: 14.7+/-2.3 pg/mL, n=6). In conclusion the results suggest that pressor responses to SON microinjection of L-glu are caused by activation of non-NMDA glutamate receptors and mediated by vasopressin release into systemic circulation.

Role of the medial prefrontal cortex in cardiovascular responses to acute restraint in rats

The medial prefrontal cortex (mPFC) modulates neurovegetative and behavioral responses, being involved in memory, attention, motivational and executive processes. There is evidence indicating that mPFC modulates cardiovascular correlates of behavioral responses to stressful stimuli. Acute restraint is an unavoidable stress situation that evokes marked and sustained cardiovascular changes, characterized by elevated blood pressure (BP) and intense heart rate (HR) increase. We presently report effects of mPFC pharmacological manipulations on BP and HR responses evoked by acute restraint in rats. Bilateral microinjection of 200 nl of the unspecific synaptic blocker CoCl2 (1 mM) in the mPFC prelimbic area (PL) increased HR response to acute restraint, without significant effect on the BP response. This result indicates that PL synaptic mechanisms have an inhibitory influence on restraint-evoked HR changes. Injections of the non-selective glutamatergic receptor antagonist kynurenic acid (0.02 M) or the selective N-methyl-d-aspartic acid (NMDA) receptor glutamatergic antagonist (LY235959) (0.02 M) caused effects similar to cobalt, suggesting that local glutamatergic neurotransmission and NMDA receptors mediate the PL inhibitory influence on restraint-related HR responses. Pretreatment with the non-non-N-methyl-D-aspartic acid glutamatergic antagonist glutamatergic antagonist glutamatergic receptor antagonist NBQX (0.02 M) did not affect restraint-related cardiovascular responses, reinforcing the idea that NMDA receptors mediate PL-related inhibitory influence. Pretreatment with the glutamatergic-receptor antagonists did not affect baseline BP or HR values. I.v. pretreatment with the quaternary ammonium anticholinergic drug homatropine methyl bromide (0.2 mg/kg) also increased the restraint-related HR response to values similar to those observed after treatment with kynurenic acid or LY235959, thus, suggesting that PL inhibitory influence on restraint-evoked heart rate increase could be related to increased parasympathetic activity. This dose of homatropine had no significant effects on baseline BP or HR values. Results suggest a PL inhibitory influence on restraint-evoked HR increase. They also indicate that local NMDA receptors involved in parasympathetic activation mediate PL inhibitory influence on restraint-evoked HR increase.

The lateral septal area is involved in the pressor pathway activated by microinjection of norepinephrine into the rat brain cingulate cortex

The cingulate cortex (CC) is involved in cardiovascular regulation. Microinjection of norepinephrine (NE) into the Cg3 area of the CC caused vasopressin release and pressor responses in unanesthetized rats. Microinjection of acetylcholine (ACh) into the lateral septal area (LSA) of unanesthetized rats caused similar vasopressin-related pressor responses. The LSA is anatomically connected to the CC and the paraventricular nucleus (PVN) of the hypothalamus, an important nucleus involved in vasopressin synthesis. Therefore, we attempted to verify if the cholinergic neurotransmission within the LSA is involved in the mediation of the pressor response to the microinjection of NE into the Cg3. Local pretreatment with lidocaine, muscimol, atropine or hemicholinium-3 microinjected into the LSA blocked the pressor response to the microinjection of NE injection into the Cg3. Conversely, pretreatment with physostigmine microinjected into the LSA potentiated the pressor response to NE injection into the Cg3. The present results indicate that the synapses in the LSA are part of the pressor pathway originating at the CC and that cholinergic neurotransmission within the LSA is involved in the mediation of the cardiovascular responses to the microinjection of NE into the Cg3.

Mechanisms involved in the pressor response to noradrenaline injection into the cingulate cortex of unanesthetized rats

The cingulate cortex (CC) is involved in cardiovascular modulation. CC electrical or chemical stimulation may evoke either pressor or depressor responses, depending on the stimulated site and experimental conditions such as anesthesia. Noradrenaline (NA) is involved in cardiovascular regulation and it is present throughout the cortex. However, there is no report on the cardiovascular effects of intracortical injections of NA. We attempted to verify the effect of NA injection into the CC and to identify possible receptor and peripheral mechanisms involved. NA injection caused pressor responses accompanied by bradycardia, in unanesthetized rats. These responses were markedly reduced under urethane anesthesia. The pressor response was blocked by intracortical pretreatment with phenoxybenzamine or the selective alpha(1)-antagonist WB4101, and it was not affected by pretreatment with the selective alpha(2)-antagonist RX821002, suggesting that alpha(1)-adrenoceptors mediate the response. The pressor response was potentiated by pretreatment with the ganglion blocker mecamylamine and it was abolished by pretreatment with the vasopressin antagonist, dTyr(CH(2)) (5)(Me)AVP or by hypophysectomy. Circulating vasopressin levels were increased after NA injection into the CC. The present results indicate that the pressor response to local injection of NA within the CC is independent of sympathetic nerve activation and is mediated by vasopressin release.

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.

[Study of intrauterine growth of normal newborn infants]

OBJECTIVE: To evaluate the intrauterine normal growth profile and its variations. To draw an intrauterine growth standard at the maternity ward of Hospital Universitário Antonio Pedro (UFF-RJ) by studying the variables of weight, length, cephalic perimeter and ponderal index, at birth, from single foetus pregnancies. We compare those curves with those in other national research works, as well as with the classical one by Lubchenco.METHODS: The starting number of 1566 live births which happened between April, 1992 and September, 1993 was cut down to 1031 due to exclusions resulting from interfering factors of foetus growth (Hypertensive Disease of Pregnancy, smoking mother, chronic arterial hypertension and major malformations). We also excluded from analysis those foetus of mothers who could not remember the date of their last period or when it was discordant in more than a week from Dubowtiźs score.RESULTS: Comparing this standard of intrauterine growth to those chosen in literature, the present values were similar to other national curves that exclude intrauterine growth interfering factors. Comparing our curve with the classical Lubchencós curve, we observed higher mean values at lower gestational ages than the ones in Denvers study, and lower late desaceleration of the ponderal gain in the present one.The Ponderal Indexes of the present study have higher mean values compared to the ones in other studies, denoting, perhaps, higher prevalence of type I, or symmetric, intrauterine growth retard pattern.CONCLUSION: This study proposes a standard which is adequate to the assessment of intrauterine growth of similar populations.