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PubMed1996

Crystalloid cardioplegia route of delivery and cardiac troponin I release.

BACKGROUND: Cardiac troponin I (CTn I) has been shown to be a marker of myocardial injury. Incomplete distribution of cardioplegic solution may be responsible for injury in jeopardized myocardial areas. The aim of this study was to compare CTn I release with respect to the route of delivery of crystalloid cardioplegia, either antegrade only or initially antegrade followed by retrograde cardioplegia for the remainder of the operation, in patients undergoing elective coronary artery bypass grafting. METHODS: Sixty patients were randomly assigned to one of two cardioplegia groups. Cardiac troponin I concentrations were measured in serial venous blood samples drawn just before cardiopulmonary bypass and after aortic unclamping at 6, 9, 12, and 24 hours and daily thereafter for 5 days. Analysis of variance with repeated measures was performed to test the effect of route of delivery, coronary disease, collateral circulation, risk of cardioplegia maldistribution, and number of grafts on release of CTn I. RESULTS: Compared with the antegrade route, the combined route offered no advantage in an unselected group of patients undergoing an elective first cardiac operation and having preserved left ventricular function. The CTn I concentration did not differ between groups for any of the samples considered. In patients with major left main coronary artery stenosis, CTn I release was significantly higher at hour 9 in the antegrade group than in the group with combined delivery. CONCLUSIONS: A combined route of delivery of crystalloid cardioplegia is beneficial in patients with major stenosis of the left main coronary artery. Cardiac troponin I sensitivity is relevant in this study. Release of CTn I should be useful in determining the best form of myocardial protection for each patient.

Aged↗
PubMed2000

Accuracy of MRI evaluation of pulmonary blood supply in patients with complex pulmonary stenosis or atresia.

Detailed imaging of pulmonary artery (PA) anatomy and significant aorto-pulmonary collaterals (APCs) is crucial for surgical planning and follow-up in patients with complex congenital heart disease (CHD) and pulmonary stenosis or atresia. Because examination by echocardiography is often technically limited and catheterization is invasive, this study evaluated the diagnostic accuracy of magnetic resonance imaging (MRI) as an alternate non-invasive tool. Thirteen patients (median age 28 years, range: 1-44 years) underwent both cardiac catheterization and MRI within a median of two months (range 0.1-8 months). Diagnoses included tetralogy of Fallot (TOF) with pulmonary atresia (n = 8), TOF with pulmonary stenosis (n = 2), single left ventricle with pulmonary stenosis (n = 2), and complex heterotaxy with pulmonary stenosis (n = 1). The MRI sequences used in this study were ECG-gated spin echo and gradient echo sequences acquired in multiple planes. Compared to catheterization, MRI had 100% sensitivity and specificity for the diagnosis of main PA (n = 6) and branch PA (n = 13) hypoplasia or stenosis, as well as discontinuous (n = 4) or absent (n = 10) branch PAs. There was complete agreement between catheterization and MRI identification of significant APCs (n = 18). Main PA atresia was noted by MRI in four patients but was not definitively seen by catheterization in any. MRI but not catheterization precisely defined the distance between discontinuous PAs and their relationship to other mediastinal structures. In conclusion, cardiac MRI is a reliable non-invasive imaging modality to define PA and APC anatomy in patients with complex pulmonary stenosis or atresia.

Adolescent↗
PubMed1999

Sensitivity, specificity, and surgical impact of somatosensory evoked potentials in descending aorta surgery.

BACKGROUND: We evaluate the efficiency of multilevel somatosensory evoked potential (SEP) monitoring for intraoperative re-establishment of blood flow to the spinal cord in 63 patients undergoing descending aorta repair. METHODS: The presence of critical vessels in a cross-clamped aortic segment was ascertained by a 15 minute SEP observation period while the segment between the clamps was vented to drain out the collateral flow. RESULTS: SEPs influenced the surgical strategy in 17 cases (27%): use of the Biomedicus in 1 traumatic rupture; critical vessel reimplantation or distal clamp replacement in 13 cases of segmental spinal ischemia; and hastening the procedure or proximal clamp replacement in 3 cases of left carotid ischemia. There were no cases of unexplained multilevel SEP abnormalities. Immediate paraplegia was observed in 2 cases (1 pre-existing; 1 forecast by a 199-minute period of SEP absence due to segmental ischemia); 2 patients presented delayed paraplegias despite unchanged intraoperative SEPs, and 1 case presented a transient paraplegia due to lower motoneuronal involvement. CONCLUSIONS: SEPs efficiently identified critical vessels to be reimplanted in order to avoid immediate paraplegia. However, systematic additional vessel reimplantation, if technically feasible, and prolongation of SEP monitoring during the postoperative period with careful blood pressure control are needed to prevent delayed paraplegia.

Adult↗
PubMed1995

Alzheimer's disease in the National Academy of Sciences-National Research Council Registry of Aging Twin Veterans. III. Detection of cases, longitudinal results, and observations on twin concordance.

OBJECTIVES: To detect cases of Alzheimer's disease (AD) in a large population of twins living throughout the United States and to examine concordance for AD in twins as a function of age and genotype for apolipoprotein E (APOE). SETTING: Nationwide survey. DESIGN: Multistage screening and field evaluation beginning with two telephone interviews and culminating with laboratory tests, longitudinal neuropsychological measures, physician examination, and diagnostic consensus among experts. PARTICIPANTS: Membership in 1990-1991 of intact pairs in the National Academy of Sciences--National Research Council Registry of veteran twins, then aged 62 to 73 years. MAIN OUTCOME MEASURES: Completeness of case detection was examined in collateral studies. Zygosity and APOE genotypes were determined by restriction mapping. Concordance was calculated by the proband method. RESULTS: Ninety subjects who screened positively for AD were studied in person, and 60 whose differential diagnoses included AD were followed up, as were their co-twins. Sensitivity of screening was estimated at greater than 99%, but 24% of subjects refused participation after initial screening. Seven of 38 diagnoses of AD have been confirmed at autopsy, and 31 other subjects eventually met criteria for probable or possible AD (prevalence estimate, 0.42%, 95% confidence interval, 0.29% to 0.56%), with good interrater reliability (intraclass r = .86). Excluding one discordant pair with unknown zygosity, concordance rates were 21.1% (4/19) for monozygotic and 11.1% (2/18) for dizygotic probands. Concordance was 50% for twins sharing the epsilon 4/epsilon 4 genotype at APOE, but there were no affected co-twins of 15 probands with onset before age 70 years, no epsilon 4 allele, and no family history of AD. The mean (SD) period of discordance in the latter pairs was 11.3 (3.3) years. CONCLUSIONS: The multistage case-detection approach achieved reliable and valid diagnoses of AD with high apparent sensitivity but substantial attrition after initial screening. Genetic influences in AD at this age are limited, except among homozygotes for allele epsilon 4 at APOE. Subjects with early-onset AD who lack the epsilon 4 allele are not rare, and their condition appears to have little genetic influence. They should be ideal for studies on environmental cause of AD.

Aged↗
PubMed2000

Musculoskeletal MR: knee.

Magnetic resonance imaging is the most sensitive, specific, and accurate noninvasive method for diagnosing internal derangement of the knee. During the past 15 years knowledge of pathologic conditions of the knee had evolved significantly. Beyond the basic principles of imaging knee injuries great impact was made on the understanding of indirect or collateral findings, even in rare diseases. In this article the spectrum of disorders of the knee are reviewed and an overview of the current literature is given. This includes considerations about how to achieve a high-standard MR imaging study of the knee, and principles of imaging anterior cruciate ligament and meniscal tears. A focus is put on distinct diseases including intra-articular and intraosseous ganglion cysts, iliotibial band friction syndrome, transient osteoporosis, osteonecrosis, osteochondritis dissecans, and imaging of the articular cartilage.

Anterior Cruciate Ligament Injuries↗
PubMedDate not supplied

Instrumented measurement of the posterolateral corner.

A new device called the Lars Rotational Laxiometer (Lars Inc, Dijon, France) is introduced to aid in the diagnosis of posterolateral rotatory instability of the knee. This device assigns a quantitative value for tibial external rotation. Three examiners each evaluated a separate group of 30 different subjects (total 180 knees) to obtain side-to-side differences. The subjects had no history of injury, pain, or instability. An external rotation measurement was performed at 30 degrees and 90 degrees of knee flexion. At 90 degrees, the mean side-to-side difference was 4.4 degrees (range, 3.7 degrees to 5.1 degrees); at 30 degrees it was 5.5 degrees (range, 4.7 degrees to 6.3 degrees). There was no significant difference with gender or age. The purpose of this study is to establish baseline side-to-side values for the posterolateral complex in normal knees. Objective values are obtainable with the Laxiometer.

Adolescent↗
PubMed2004

Individual resistance to cerebral ischemia and negative effect of emotional stress on the course of this disorder.

The ratio of low-activity and high-activity rats differed in autumn, winter, and spring litters. Initially more intensive cerebral blood flow in low-active rats and its more pronounced decrease after common carotid artery occlusion determined their higher sensitivity to cerebral ischemia (compared to high-activity animals). After 18-h immobilization stress cerebral blood flow decreased by 10-15%, which abolished the difference in the individual resistance to cerebral ischemia. Independently on emotional resistance, cerebral ischemia was not accompanied by the development of collateral blood flow in the acute period and caused death of 90% rats.

Animals↗
PubMedDate not supplied

Field effects trigger post-anodal rebound excitation in vertebrate CNS.

Although both chemical and electrotonic synaptic interactions have often been implicated in normal and pathophysiological conditions where clusters of central neurones discharge in unison, in many instances the mechanisms underlying synchrony in the vertebrate central nervous system remain obscure. Another form of cellular communication which can be invoked is that of field effects, defined here as electrical interactions mediated across extracellular space. Studies of the goldfish Mauthner (M-) cell provided the first clear evidence for such interactions, which have now been shown to exist in various mammalian central structures. A single impulse in the M-cell leads to the nearly simultaneous firing of 40 to 80 interneurones which feed inhibition back onto it, by both direct synaptic excitation and a field effect, which is initially hyperpolarizing. On the basis of early observations on this system, it was suggested that field effects could induce or facilitate synchronized and even epileptic-like neuronal bursting. We report here that the inhibitory interneurones exhibit a remarkably sensitive anodal break excitation triggered by a brief hyperpolarization comparable to the electrical inhibition mentioned above. This mechanism alone may be sufficient to recruit a second class of these interneurones, which are postsynaptic to eighth nerve afferents and do not receive chemical synaptic input from the collateral network. The rebound facilitation is distinguished from excitatory field effects which can also contribute to synchronization.

Animals↗
PubMed1979

Genetic control of enhanced mutability of mitochondrial DNA and gamma-ray sensitivity in Saccharomyces cerevisiae.

Five nuclear mutants enhancing the spontaneous mutation rate of mtDNA have been isolated in Saccharomyces cerevisiae. These mutators fall into five complementation groups and are located at five genetic loci different from rad50 to rad57 loci. Three mutants (gam1, gam2, and gam4), insensitive or weakly sensitive to gamma-rays, exhibit increased frequency of spontaneous production of mutants with large deletions of the mtDNA (p-) and of all tested mitochondrial drug-resistant mutants. Two other mutants (gam3 and gam5), highly sensitive to gamma-rays, increase only the mutation rate of particular alleles of the mtDNA. The mutant gam5 enhances only the production of p- and erythromycin-resistant clones. The mutant gam3 exhibits an enhanced rate of oligomycin-resistant clones as well as a collateral increase of nuclear mutability. The existence of gam3 and gam5 mutants indicates that at least two common steps control both nuclear DNA repair and the mutability of particular alleles of the mtDNA. However, the general spontaneous mutability of the mtDNA includes at least three steps not involved in the repair of nuclear DNA, as revealed by the gam1, gam2, and gam4 mutations.

Chromosome Mapping↗
PubMed2005

Effects of vasopressin on portal-systemic collaterals of cirrhotic rats.

OBJECTIVE: Arginine vasopressin (AVP) exerts a constrictive effect on the portal-systemic collaterals of non-cirrhotic portal hypertensive rats, but its effect on cirrhotic rats is unknown. The aim of this study was to investigate the response of AVP and the modulatory roles of nitric oxide and prostaglandin on collaterals of common bile duct-ligated (BDL) cirrhotic rats. MATERIAL AND METHODS: The collateral vascular responsiveness to graded concentrations of AVP (10(-10) - 3 x 10(-7) M) was tested by an in situ collateral perfusion system pretreated with Nomega-nitro-L-arginine (L-NNA, 100 microM), indomethacin (INDO, 10 microM), or both. The collateral responses to AVP with the pretreatment of a vasopressin V1 receptor antagonist d(CH2)5Tyr(Me) arginine vasopressin or a V2 receptor agonist 1-desamino-8-D-arginine vasopressin (DDAVP, 10(-10) - 3 x 10(-7) M) were also evaluated. RESULTS: The perfusion pressure of collaterals was significantly increased by AVP, and this effect was inhibited by the addition of the V1 receptor antagonist. DDAVP had no effect on the collaterals. Incubation with L-NNA or L-NNA plus INDO, but not INDO alone, significantly potentiated the constrictive effects of AVP. The constrictive effect of AVP in the combination group was similar to that in the L-NNA alone group. CONCLUSIONS: The results show that AVP produces a direct vasoconstrictive effect on the portal-systemic collaterals of BDL cirrhotic rats. The constrictive effect of AVP is mediated by the vasopressin V1, instead of V2, receptors. Nitric oxide may play a more important role than prostaglandin in modulating the collateral vascular response to AVP in BDL cirrhotic rats.

Animals↗
PubMed1995

Noninvasive evaluation of the collateral circulation to the hand.

OBJECTIVE: To compare four methods of evaluating collateral blood flow to the hand. METHODS: The hands of 74 volunteers on the faculty or staff of a university hospital were studied prospectively. Only subjects without known peripheral vascular disease were included. Four tests were used in random order to assess radial and ulnar artery flow. Results of the assessments using the modified Allen's test, pulse oximetry, plethysmography, and laser Doppler perfusion monitoring were compared. RESULTS: No interrupted palmar arch was found. The modified Allen's test was normal in all cases. Pulse oximetry detected a 5% incidence of noticeably reduced blood flow in one artery compared with the other artery. This dominance of one artery was identified in 69% of the hands by plethysmography. The laser Doppler noted a dominant artery in 64% of the hands. Plethysmography and the laser Doppler disagreed in their findings in only 9% of the hands evaluated. Numerical values of blood flow, attainable only by the laser Doppler, were significantly lower upon occlusion of the radial vs the ulnar arteries (p < 0.05; paired t-test). CONCLUSION: All of the tests provide information about the collateral circulation to the hand. Only the laser Doppler provides quantitative blood flow. Further studies involving subjects most at risk for post-cannulation ischemic injury are needed to guide the clinical application of these findings.

Adult↗
PubMed2002

The nicotinic allosteric potentiating ligand galantamine facilitates synaptic transmission in the mammalian central nervous system.

In this study, the patch-clamp technique was used to determine the effects of galantamine, a cholinesterase inhibitor and a nicotinic allosteric potentiating ligand (APL) used for treatment of Alzheimer's disease, on synaptic transmission in brain slices. In rat hippocampal and human cerebral cortical slices, 1 microM galantamine, acting as a nicotinic APL, increased gamma-aminobutyric acid (GABA) release triggered by 10 microM acetylcholine (ACh). Likewise, 1 microM galantamine, acting as an APL on presynaptically located nicotinic receptors (nAChRs) that are tonically active, potentiated glutamatergic or GABA-ergic transmission between Schaffer collaterals and CA1 neurons in rat hippocampal slices. The cholinesterase inhibitors rivastigmine, donepezil, and metrifonate, which are devoid of nicotinic APL action, did not affect synaptic transmission. Exogenous application of ACh indicated that high and low levels of nAChR activation in the Schaffer collaterals inhibit and facilitate, respectively, glutamate release onto CA1 neurons. The finding then that the nAChR antagonists methyllycaconitine and dihydro-beta-erythroidine facilitated glutamatergic transmission between Schaffer collaterals and CA1 neurons indicated that in a single hippocampal slice, the inhibitory action of strongly, tonically activated nAChRs in some glutamatergic fibers prevails over the facilitatory action of weakly, tonically activated nAChRs in other glutamatergic fibers synapsing onto a given neuron. Galantamine is known to sensitize nAChRs to activation by low, but not high agonist concentrations. Therefore, at 1 microM, galantamine is likely to increase facilitation of synaptic transmission by weakly, tonically activated nAChRs just enough to override inhibition by strongly, tonically activated nAChRs. In conclusion, the nicotinic APL action can be an important determinant of the therapeutic effectiveness of galantamine.

Action Potentials↗
PubMed2000

CO(2) wedged hepatic venography in the evaluation of portal hypertension.

BACKGROUND/AIMS/METHODS: During hepatic vein catheterisation, in addition to measurement of hepatic venous pressure gradient (HVPG), iodine wedged retrograde portography can be easily obtained. However, it rarely allows correct visualisation of the portal vein. Recently, CO(2) has been suggested to allow better angiographic demonstration of the portal vein than iodine. In this study we investigated the efficacy of CO(2) compared with iodinated contrast medium for portal vein imaging and its role in the evaluation of portal hypertension in a series of 100 patients undergoing hepatic vein catheterisation, 71 of whom had liver cirrhosis. RESULTS: In the overall series, CO(2) venography was markedly superior to iodine, allowing correct visualisation of the different segments of the portal venous system. In addition, CO(2), but not iodine, visualised portal-systemic collaterals in 34 patients. In cirrhosis, non-visualisation of the portal vein on CO(2) venography occurred in 11 cases; four had portal vein thrombosis and five had communications between different hepatic veins. Among non-cirrhotics, lack of portal vein visualisation had a 90% sensitivity, 88% specificity, 94% negative predictive value, and 83% positive predictive value in the diagnosis of pre-sinusoidal portal hypertension. CONCLUSIONS: Visualisation of the venous portal system by CO(2) venography is markedly superior to iodine. The use of CO(2) wedged portography is a useful and safe complementary procedure during hepatic vein catheterisation which may help to detect portal thrombosis. Also, lack of demonstration of the portal vein in non-cirrhotic patients strongly suggests the presence of pre-sinusoidal portal hypertension.

Carbon Dioxide↗
PubMedDate not supplied

MR angiography of the portal venous system: techniques, interpretation, and clinical applications.

Magnetic resonance (MR) angiography is a noninvasive means of assessing the portal venous system that has potential advantages over currently used modalities. Time-of-flight and phase-contrast MR angiography are useful techniques that differ fundamentally in their means of data acquisition but are comparable in their ability to demonstrate normal anatomy as well as abnormalities of the portal venous system. Occasionally, artifacts caused by respiratory motion, implanted metallic devices or surgical clips, in-plane saturation, or areas of complex flow are seen at MR angiography of the portal venous system. However, most artifacts can easily be identified as such and either remedied or ignored. In addition, the suppression of signal from surrounding soft tissues may result in poor detection of parenchymal lesions. The utility of standard projection angiograms and source images can be increased through the use of intravenously administered contrast material and postprocessing techniques such as partial-volume maximum intensity projection reconstructions and shaded surface renderings. In addition to providing information on portal venous anatomy and portosystemic collateral vessels, MR angiography of the portal vein has clinical application in portal venous thrombosis and stenosis, liver transplantation, and the evaluation and planning of surgical and transjugular intrahepatic portosystemic shunts.

Algorithms↗
PubMedDate not supplied

Color Doppler imaging of posttraumatic priapism before and after selective embolization.

High-flow priapism usually follows perineal or penile trauma with disruption of an intracavernosal artery. Angiographic embolization of the lacerated artery is currently considered the treatment of choice. The contribution of gray-scale and color Doppler ultrasonography (US) in diagnosis and treatment of 10 patients with high-flow priapism was investigated. In patients with recent arterial laceration, the cavernous tissue surrounding the arterial-sinusoidal fistula appears as a hypoechoic region with undefined margins. In long-standing priapism, this area is usually more regular and circumscribed, mimicking a pseudoaneurysm. Color Doppler US is highly sensitive for detection of the arterial-sinusoidal fistula that causes extravasation of blood from the lacerated cavernosal artery. After angiography, color Doppler US allows confirmation of both successful embolization by demonstrating disappearance or size reduction of the fistula and unsuccessful treatment by demonstrating patency of collateral feeding vessels or early recanalization of the embolized artery. Limitations of color Doppler US include underestimation of the number of accessory feeding vessels, which may become patent only after embolization of the main vascular supply, and difficulty in recognizing vessels that feed the fistula from the opposite side.

Adolescent↗
PubMed2005

Hippocampal CA1 circuitry dynamically gates direct cortical inputs preferentially at theta frequencies.

Hippocampal CA1 pyramidal neurons receive intrahippocampal and extrahipppocampal inputs during theta cycle, whose relative timing and magnitude regulate the probability of CA1 pyramidal cell spiking. Extrahippocampal inputs, giving rise to the primary theta dipole in CA1 stratum lacunosum moleculare, are conveyed by the temporoammonic pathway. The temporoammonic pathway impinging onto the CA1 distal apical dendritic tuft is the most electrotonically distant from the perisomatic region yet is critical in regulating CA1 place cell activity during theta cycles. How does local hippocampal circuitry regulate the integration of this essential, but electrotonically distant, input within the theta period? Using whole-cell somatic recording and voltage-sensitive dye imaging with simultaneous dendritic recording of CA1 pyramidal cell responses, we demonstrate that temporoammonic EPSPs are normally compartmentalized to the apical dendritic tuft by feedforward inhibition. However, when this input is preceded at a one-half theta cycle interval by proximally targeted Schaffer collateral activity, temporoammonic EPSPs propagate to the soma through a joint, codependent mechanism involving activation of Schaffer-specific NMDA receptors and presynaptic inhibition of GABAergic terminals. These afferent interactions, tuned for synaptic inputs arriving one-half theta interval apart, are in turn modulated by feedback inhibition initiated via axon collaterals of pyramidal cells. Therefore, CA1 circuit integration of excitatory inputs endows the CA1 principal cell with a novel property: the ability to function as a temporally specific "AND" gate that provides for sequence-dependent readout of distal inputs.

Animals↗
PubMed1999

Viral-induced cirrhosis: grading of severity using MR imaging.

OBJECTIVE: The purpose of this study was to determine whether MR imaging can be used to grade the severity of cirrhosis. MATERIALS AND METHODS: The MR examinations of 46 patients with cirrhosis were retrospectively reviewed independently by two radiologists and correlated with clinical severity assessed by Child-Pugh classification. MR imaging analysis by reviewers who were unaware of clinical status included comparison of volume indexes (computed as the product of three axis measurements) of the spleen and each segment of the liver, and changes in hepatic contour, iron or fat deposition, and presence of varices and collaterals. RESULTS: Volume index of the spleen and the presence of ascites and varices were significantly and positively correlated (p = .008, .002, .0001, respectively) with the clinical severity of cirrhosis (Child-Pugh classifications), and volume indexes of the posterior, medial, and lateral segments of the liver were significantly and inversely correlated (p = .001, .049, .041, respectively). On an MR scoring system based on four items (volume index of the spleen; volume index of posterior + medial + lateral segments; presence of ascites; and presence of varices and collaterals), averaged total MR scores were 2.5 +/- 0.3, 4.9 +/- 0.6, and 7.9 +/- 0.8 for Child-Pugh grades A, B, and C, respectively (p < .0001). The accuracy of MR scoring in distinguishing between clinical Child-Pugh grade A cirrhosis and further grades was 89%, the sensitivity was 93%, and the specificity was 82%. CONCLUSION: An MR scoring system can be used to grade the severity of cirrhosis.

Contrast Media↗
PubMed2001

Neonatal exposure to a novel environment enhances the effects of corticosterone on neuronal excitability and plasticity in adult hippocampus.

Electrophysiological studies have shown that activation of glucocorticoids receptors (GRs) influences neuronal excitability and activity dependent synaptic plasticity. In developmental studies, early life stimulation such as neonatal handling results in an up-regulation of glucocorticoid-receptor (GR) binding in the hippocampus that persists into adulthood. It is, therefore, hypothesized that early environment-induced changes in receptor sensitivity to corticosterone (CORT) might have functional effects on adult neuronal excitability and synaptic plasticity. To test this hypothesis, we exposed rats daily from post-natal days 1-21 to a non-home environment for 3 min. When the animals became adults, we studied the effects of glucocorticoid hormone corticosterone (CORT) on population spike (PS) amplitude and long-term potentiation of population spikes (PS-LTP) in vitro in the hippocampal CA1 region following activation of the Schaffer collateral fibers. Bath application of CORT reduced PS amplitude and subsequent induction of PS-LTP. This inhibitory effect of CORT was significantly greater in the slices from the novelty exposed rats (Novel) than the control rats that remained in their home cage (Home). Inhibition of population spike amplitude during CORT perfusion was 28.0+/-5.3% of baseline in Novel slices, and 9.1+/-4.4% in Home slices. CORT pre-exposure (20 min) also inhibited the subsequent induction of PS-LTP in Novel slices by 57.7+/-17.7% and by 7.5+/-12.1% in Home slices. These results provide electrophysiological evidence that neonatal novelty exposure results in functional increases in receptor sensitivity to CORT that enhances the inhibitory effects of CORT on field CA1 neuronal excitability and plasticity.

Action Potentials↗