Effects of ovariectomy and estradiol replacement on the binding of 125I-neurotensin in rat suprachiasmatic nucleus

Distribution and density of specific high-affinity 125I-neurotensin-binding sites were examined by light microscopic radioautography in the suprachiasmatic nucleus (SCN) of normal cycling, ovariectomized, or ovariectomized and estradiol-implanted female rats. In all three experimental groups, intense 125I-neurotensin labeling was detected within the ventrolateral component of the SCN. Whereas the topographic distribution and spread of the label was similar between each group, the density of the label was significantly higher (mean increase: 122%) in ovariectomized than in normally cycling females within the rostral third of the SCN. This effect was no longer apparent in females chronically implanted with estradiol at the time of gonadectomy. These results indicate that plasma gonadal steroids may regulate neurotensin receptors in the rat SCN. It is suggested that this mechanism might be implicated in the feedback control of gonadotropin and prolactin secretion.

Isolation of a cDNA clone from the B-G subregion of the chicken histocompatibility (B) complex

The B-G antigens are highly polymorphic antigens encoded by genes located within the major histocompatibility complex (MHC) of the chicken, the B system. The B-G antigens of the chicken MHC are found only on erythrocytes and correspond to neither MHC class I nor class II antigens. Several clones were selected from a lambda gt11 erythroid cell expression library by means of rabbit antisera prepared against a purified, denatured B-G antigen. One clone chosen for further study, lambda bg28, was confirmed as a B-G subregion cDNA clone by the results obtained through using it as a nucleic acid hybridization probe. In Northern hybridizations lambda bg28 anneals specifically with erythroid cell mRNA. In Southern blot analyses the lambda bg28 clone could be assigned to the B system-bearing microchromosome of the chicken karyotype on the basis of its hybridization to DNA from birds disomic, trisomic, and tetrasomic for this microchromosome. The cDNA clone was further mapped to the B-G subregion on the basis of its pattern of hybridization with DNA from birds of known B region recombinant haplotypes. Southern blot analyses of the hybridization of lambda bg28 with genomic DNA from birds of known haplotypes strongly suggest that the B-G antigens are encoded by a highly polymorphic multigene family.

Biochemical confirmation of recombination within the B-G subregion of the chicken major histocompatibility complex

Analysis of the B-G antigens of eight chicken major histocompatibility complex (B) system recombinant haplotypes by high resolution two-dimensional gel electrophoresis has provided evidence for the transfer of the complete B-G subregion in seven cases. In the eighth, a partial duplication within the B-G subregion appears to have occurred. In this recombinant, the entire array of polypeptides associated with one parental allele, B-G23, is expressed together with nearly the entire array of B-G polypeptides of the other parental haplotype, B2. This compound polypeptide pattern corroborates the serological evidence for a partial duplication within the B-G subregion and provides indirect evidence for the existence of multiple loci within B-G and for a means by which polymorphism may be introduced into the chicken major histocompatibility complex.

Internalization of (125I) alpha-bungarotoxin into rat suprachiasmatic nucleus neurons and dendrites

The distribution and rate of internalization of (125I) alpha-bungarotoxin (alpha-BuTX) was evaluated by quantitative electron microscopic autoradiography in rat suprachiasmatic nucleus. The ultrastructural distribution of silver grains was studied by both line source and 50% probability circle analyses. Line source analysis demonstrated that with increasing time following intracerebroventricular infusion, ligand is internalized from neuronal membranes. At all time points, real grain distribution was significantly different from randomly generated hypothetical grains. Quantification of silver grain localization by probability circle analysis indicated that membrane bound sources were mainly associated with axo-dendritic appositions, regardless of the length of time the tissue was exposed to radioligand. The compartment containing synaptic terminals was the most enriched when comparing real to hypothetical grains. By eight hours after intracerebroventricular infusion of specifically labelled alpha-BuTX binding sites were most likely to be within neurons and dendrites. These studies demonstrate that the majority of alpha-BuTX binding sites remain membrane bound with respect to time and may be associated with synaptic transmission; a significant proportion of silver grains are internalized within SCN neurons and dendrites.

Ultrastructural distribution of alpha-bungarotoxin binding sites in the suprachiasmatic nucleus of the rat hypothalamus

The distribution of (125I) alpha bungarotoxin (alpha-BTX) binding sites in the suprachiasmatic nucleus (SCN) of the adult female rat was examined by electron-microscopic autoradiography. The ultrastructural distribution of silver grains was analysed by line source, direct point count, and 50% probability circle methods. Real grain distribution was significantly different from that of randomly generated hypothetical grains. Line source analysis demonstrated two populations of sources: one associated with membranes, and one inside neuronal structures. Probability circle analysis of shared grains indicated that membrane-bound-radioactive sources were mainly associated with axo-dendritic appositions. Only a small proportion of labeled neuronal interfaces exhibited synaptic differentiations in the plane of section. However, the compartment containing synaptic terminals was the most enriched when comparing real to hypothetical grains. Probability circle analysis of exclusive grains demonstrated that sources that were not associated with neuronal plasma membranes were likely to be within nerve cell bodies and dendrites. It is concluded that the majority of specifically labelled alpha-BTX binding sites in the SCN is membrane bound, and may be associated with axodendritic synaptic transmission. The presence of a significant proportion of the label in the soma and dendrites of suprachiasmatic neurons 24 h after ventricular infusion suggests that some of the labeled binding sites (junctional or nonjunctional) may be internalized within these two compartments.

Effects of the Mueller maneuver on global and regional left ventricular function in angina pectoris with or without previous myocardial infarction

In patients with coronary artery disease, left ventricular (LV) regional wall akinesia can develop during the Mueller maneuver. The present study determines if the presence of myocardial ischemic disease with no infarction is a sufficient condition for this to occur, or if the presence of prior acute myocardial infarction (MI) is necessary. In men, first-pass radionuclide ventriculography was performed in the 30 degree left anterior oblique supine position to measure LV ejection fraction, end-diastolic and end-systolic volumes and heart rate, and to obtain an image of the LV cavitary perimeter. This procedure was performed in 4 subject groups: 13 normal volunteers, 25 patients with coronary artery disease but no prior MI, 13 patients with coronary artery disease and prior nontransmural MI, and 36 patients with coronary artery disease and prior transmural MI. All patients had angina and underwent routine contrast coronary angiography; 60 also underwent contrast coronary angiography; 60 also underwent contrast LV angiography. Ejection fraction decreased during the Mueller maneuver in each of all the coronary artery disease groups (p less than 0.01), but not in the normal subjects. Heart rate increased in groups 1, 2 and 4 (p less than 0.01), and end-diastolic volume decreased in all 4 groups (p less than 0.01), whereas end-systolic volume did not change. Only in group 4 did regional wall akinesia develop (17 patients) during the Mueller maneuver. Among patients who had akinesia during the Mueller maneuver and also underwent routine contrast ventriculography, half of the akinetic segments were not seen on routine contrast study, but were seen only on radionuclide ventriculography during the Mueller maneuver.(ABSTRACT TRUNCATED AT 250 WORDS)

The influence of estrous cycle and intrastriatal estradiol on sensorimotor performance in the female rat

The influence of estrous cycle and intrastriatal implants of 17 beta-estradiol (17 beta-estradiol). 17 alpha-estradiol (17 alpha-estradiol) or cholesterol on the number of footfaults made by female rats traversing a narrow suspended beam was investigated. Female rats made fewer footfaults on estrus than on other days of the cycle. This was true when testing occurred during either the light or dark phase of the light:dark cycle. Intrastriatal implants of 30% 17 beta-estradiol for 6 hours resulted in a significant improvement in sensorimotor performance as soon as 4 hours after hormone implant and persisting for days. In contrast, intrastriatal implants of either 30% 17 alpha-estradiol or cholesterol had no influence on performance. The extent of hormone diffusion away from the implant cannula was minimal, and the resulting concentration of 17 beta-estradiol in the striatum was less than 10 pg/mg. It is concluded that estradiol has a direct, stereospecific effect in the striatum that influences performance of a skilled motor act in the female rat.

Psychotic and nonpsychotic depressions: I. Comparison of plasma catecholamines and cortisol measures

Unconjugated plasma catecholamines and cortisol were measured before and after a 1 mg dose of dexamethasone in 22 medication-free depressed patients and 6 healthy, medication-free control subjects. Plasma dopamine (DA) levels in the psychotically depressed subgroup (n = 4) were significantly higher both before and after dexamethasone than those in the nonpsychotic depressed group and higher before dexamethasone than in the control group. Similarly, the psychotically depressed group exhibited significantly higher cortisol levels both before and after dexamethasone than the nonpsychotic depressed group or the control group. In contrast, the psychotically depressed group had significantly lower postdexamethasone plasma norepinephrine levels compared to the nonpsychotic depressed group. In both patients and controls, plasma DA was significantly higher after dexamethasone administration than before, but the magnitude of the increase was 10 times greater in controls than in patients.

Chick embryonic erythrocyte antigen--tissues sharing expression

There is an antigenic glycoprotein (Mr 48 kD) present on the surfaces of erythrocytes of embryonic and young chickens that cannot be detected on the circulating erythrocytes in adult birds. This antigen, generally defined by this differential expression, has been thought to be associated with the maturation of hematopoietic tissues. We now present evidence, based on the use of a monoclonal antibody, maEE1, and the characteristic pattern of this glycoprotein on two-dimensional (2D) gels, that this antigen, which we have named chickEE, is expressed in a number of other embryonic and adult tissues. Immunofluorescent labeling of cryosections and flow-cytometric analysis of cells labeled with maEE1 have revealed the presence of chickEE in the retina (present in all layers), in muscle tissues (present in the endomysium and within the vascular endothelium), in the liver (especially evident on the lateral surface of hepatocytes and within the sinusoids), on epithelia such as the gut and kidney tubule epithelium and within lymphoid organs (present on bursacytes, splenocytes, thymocytes and peripheral leukocytes, and again within the endothelium) of young and adult animals. The 2D gel patterns of chickEE derived from embryonic tissues (retina, hind limb, thymus and bursa) and the adult tissues (retina and spleen) are very similar to that of the embryonic erythrocyte. Thus, the extended reactivity of the monoclonal antibody to chickEE, maEE1, with additional tissues is, in at least the tissues examined, based on the presence of the chickEE glycoprotein and not on incidental cross-reactivity. The evidence presented in this paper for the widely-shared expression of chickEE antigen makes it necessary to reconsider the function of this component of the cell surface.

Competitive interaction of pirenzepine with rat brain muscarinic acetylcholine receptors

In the present work, we studied the details of the interaction of the nonclassical muscarinic receptor antagonist pirenzepine with [3H]quinuclidinyl benzilate binding sites in rat brain homogenates. Pirenzepine showed biphasic competition curves with a Hill coefficient lower than unity, and these curves were better described according to a two-site receptor model. The affinities and the relative preponderance of these sites were constant at different ligand concentrations, in accordance with a competitive type of interaction. Similarly, pirenzepine did not influence the rate of dissociation of the [3H]quinuclidinyl benzilate-receptor complex, even at relatively high concentrations. However, although low concentrations of pirenzepine decreased the affinity of [3H]quinuclidinyl benzilate for the receptor without affecting the density of the binding sites, higher concentrations of the antagonist decreased the receptor number in a reversible fashion. Schild plots of these data indicated an apparent deviation from simple competition in this experimental design, an observation which can be attributed to the selectivity of pirenzepine for different receptor subtypes. Furthermore, pirenzepine, at concentrations high enough to saturate both its high- and low-affinity sites protected [3H]quinuclidinyl benzilate binding sites in the brain against irreversible alkylation by propylbenzilylcholine mustard. Therefore, our data support a competitive nature of interaction of pirenzepine with rat brain muscarinic receptors.

Human and canine ventricular vasoactive intestinal polypeptide: decrease with heart failure

Vasoactive intestinal polypeptide (VIP) is a systemic and coronary vasodilator that may have positive inotropic properties. Myocardial levels of VIP were assayed before and after the development of heart failure in two canine models. In the first, cobalt cardiomyopathy was induced in eight dogs; VIP (by radioimmunoassay) decreased from 35 +/- 11 pg/mg protein (mean +/- SD) to 5 +/- 4 pg/mg protein (P less than 0.05). In six dogs with doxorubicin-induced heart failure, VIP decreased from 31 +/- 7 to 11 +/- 4 pg/mg protein (P less than 0.05). In addition, VIP content of left ventricular muscle of resected failing hearts in 10 patients receiving a heart transplant was compared with the papillary muscles in 14 patients (five with rheumatic disease, nine with myxomatous degeneration) receiving mitral valve prostheses. The lowest myocardial VIP concentration was found in the hearts of patients with coronary disease (one patient receiving a transplant and three receiving mitral prostheses) (6.3 +/- 1.9 pg/mg protein). The other patients undergoing transplantation had an average ejection fraction of 17% +/- 6% and a VIP level of 8.8 +/- 3.9 pg/mg protein. The hearts without coronary artery disease (average ejection fraction of this group 62% +/- 10%) had a VIP concentration of 14.1 +/- 7.9 pg/mg protein, and this was greater than in hearts of the patients with coronary disease and the hearts of patients receiving a transplant (P less than 0.05). Myocardial catecholamines were also determined in 14 subjects; a weak correlation (r = 0.57, P less than 0.05) between the tissue concentrations of VIP and norepinephrine was noted.(ABSTRACT TRUNCATED AT 250 WORDS)

A quantitative and morphometric evaluation of 125I-alpha-bungarotoxin binding in the rat hypothalamus

The distribution of 125I-alpha-bungarotoxin (alpha-BTX), a putative nicotinic cholinergic receptor ligand was studied both in vitro and in vivo in the suprachiasmatic nucleus (SCN), anterior hypothalamic area (AHA), and supraoptic nucleus (SON) of the hypothalamus. For in vitro studies 20 micron frozen frontal sections containing SCN were incubated with either radioligand or, unlabeled alpha-BTX plus 125I alpha-BTX and tissues were processed for light microscopic autoradiography. Areas of cresyl violet stained SCN sections were measured using a Bioquant Analysis System and grain counts and distributions were determined. For in vivo investigations third ventricular infusion of either 125I alpha-BTX, or unlabeled alpha-BTX with 125I alpha-BTX was performed, and 24 hours later animals were perfused pericardially and 1 micron serial plastic sections of the SCN were processed for light microscopic autoradiography. Localization of silver grains in 1 micron serial sections was evaluated in a double blind study. In vitro and in vivo labeling patterns in the hypothalamus were the same and compared well with previously examined paraffin-processed tissues from animals which had received third ventricular infusions of the neurotoxin. We observed a distinctive and specific labeling pattern of the SCN. Grains tended to localize diffusely and uniformly in more rostral regions, but clustered densely in the dorsal and lateral mid-SCN, and dorsally in the mid-caudal SCN. Grains were localized in the SCN where larger neurons were found. In the most caudal regions of the SCN no labeling was observed. Tissues from unlabeled alpha-BTX plus 125I alpha-BTX in vitro or in vivo studies did not demonstrate grain counts above background levels.(ABSTRACT TRUNCATED AT 250 WORDS)

Relationship of putative nicotinic cholinergic receptors in the suprachiasmatic nucleus to levels of pineal serotonin N-acetyltransferase activity in the normally cycling female, the male, and the ovariectomized rat

We have examined the nocturnal increase in pineal serotonin N-acetyltransferase (SNAT) activity in the rat and the decrease in activity of this enzyme as a result of exposure of the rats to light during the nocturnal period. In females with normal ovulatory cycles and ovariectomized females, levels of the enzyme were similar during the dark (695 +/- 70 pmol/min/gland vs. 590 +/- 68) or after 20 min of lights on at night (107 +/- 5 vs. 105 +/- 8). Carbachol, a cholinergic agonist, was injected at 2400 hr (EST) into the lateral ventricle of orbitally enucleated rats. The agonist simulated the lights on effect in both intact and ovariectomized rats. Highly purified fractions of alpha-bungarotoxin, a nicotinic cholinergic antagonist were injected into either the third ventricle or bilaterally adjacent to the SCN in intact females, intact males, or ovariectomized rats. These injections had no effect on either the nighttime increase or the lights on inhibition of SNAT. This study makes the following observations: 1) As was previously demonstrated [Illnerova, H. Endocrinol. Exp. 9:141-148, 1975], ovariectomy affects neither the daytime (light period) nor nighttime (dark period) activity of pineal SNAT. This study extends previous work by demonstrating that ovariectomy also has no effect on the lights on at night decrease of SNAT activity. 2) This study confirms that intraventricular infusion of carbachol decreases the nocturnal pineal SNAT activity [Zatz, M., and Brownstein, M.J. Brain Res. 213:438-442, 1981]. 3) This study does not confirm the report that the nicotinic cholinergic antagonist alpha-bungarotoxin prevents the loss of nocturnal SNAT activity induced by turning lights on at night [Zatz, M., and Brownstein, M.J. Brain Res. 213:438-442, 1981].

Effect of vasoactive intestinal polypeptide on the canine cardiovascular system

Our purpose was to determine the effect of vasoactive intestinal polypeptide (VIP) on the cardiovascular system with special emphasis on coronary vascular effects. In section I, VIP was infused into six healthy and six cobalt-cardiomyopathic dogs at two infusion rates (0.02 and 0.05 micrograms/kg/min). Left ventricular end diastolic pressure and mean systemic pressure fell significantly in both groups. Heart rate rose in both, and maximum systolic dP/dt increased in the myopathic group. Cardiac output and regional blood flows were determined by serial left atrial injections of radioactive 15 +/- 3 mum (mean +/- SD) microspheres. In both groups, blood flow increased significantly to the esophagus, pancreas, atria, and ventricles and to the endocardial and epicardial regions of the left ventricular free wall. Blood flow to the brain decreased. In section II, VIP was infused intravenously at 0.1 micrograms/kg/min into six anesthetized dogs with coronary sinus flow, pulmonary artery, and systemic artery catheters inserted. Cardiac index rose from baseline (3.1 +/- 0.5 to 4.8 +/- 1.3 L/min/m2, P less than 0.005), as did coronary blood flow (90 +/- 25 to 159 +/- 54 ml/min, P less than 0.005) during the VIP infusion. Myocardial oxygen consumption rose from 14.1 +/- 3.9 to 19.8 +/- 5.4 ml/min (P less than 0.001), but the aorta-to-coronary sinus O2 difference decreased from 157 +/- 19 ml/L to 132 +/- 42 ml/L (P less than 0.05), and the percent O2 extracted from coronary blood also decreased significantly.(ABSTRACT TRUNCATED AT 250 WORDS)

Primary angiosarcoma of the innominate vein: a case report with resection and long-term survival

The first reported case of a primary angiosarcoma arising from the innominate vein is presented. This rare tumor was treated with surgical excision, and the patient is alive 8 years postoperatively.

The effects of a single acute dose of dexamethasone on monoamine and metabolite levels in rat brain

Twenty male Sprague-Dawley rats were injected intraperitoneally with either 20 micrograms of dexamethasone or an equivalent volume of saline. The rats were then sacrificed at either one or four hours after the injections and their brains analyzed for monoamine and metabolite content using High Performance Liquid Chromatography with Electrochemical Detection. Significant effects were seen in dopaminergic and serotonergic systems, but these effects varied depending on the area of rat brain studied. Significant increases in dopamine (DA) levels were seen in the hypothalamus and nucleus accumbens of the dexamethasone treated rats when compared with saline treated rats. There was no significant effect of dexamethasone on DA levels in frontal or striatal brain areas. In the dexamethasone treated rats a significant increase in serotonin (5-HT) was observed in the hypothalamus; a significant decrease in 5-HT was observed in the frontal cortex. Biological and clinical implications of these findings are discussed.

Improvement in amino acid use in the critically ill patient with parenteral formulas enriched with branched chain amino acids

To assess the value of BCAA enriched solutions in patients under stress, we studied five critically ill, intensive care unit patients requiring total parenteral nutrition. Two complete feeding solutions were compared: one containing 15.6 per cent of the amino acids as BCAA and the other enriched to contain 50 per cent as BCAA. These solutions were prepared to be isocaloric and isonitrogenous and were administered in consecutive 24 hour periods. The order of administration was determined randomly. In the last ten hours of each infusion day, 50 microcuries of L-[1-14C]leucine were added to the solution to estimate leucine kinetics. Increased plasma leucine appearance (from 3.92 +/- 0.48 to 6.26 +/- 0.51 millimoles per hour, p less than 0.05), oxidation (from 0.83 +/- 0.23 to + 1.41 +/- 0.33 millimoles per hour, p less than 0.05) and net leucine balance (from + 0.48 +/- 0.23 to + 1.41 +/- 0.33 millimoles per hour, p less than 0.05) were found in patients while receiving the solution enriched to contain 50 per cent of the amino acids as BCAA. Plasma leucine, isoleucine and valine concentrations were also significantly increased with administration of the BCAA enriched solution, whereas plasma levels of glycine, tyrosine and phenylalanine were significantly reduced. These changes represent a normalization of plasma amino acid levels with administration of BCAA enriched solution. In addition, the improved net leucine balance observed during administration of BCAA suggests patients have an improved protein balance while receiving BCAA enriched solutions.

Liposome entrapment enhances the hypocalcemic action of parenterally administered calcitonin

The hypocalcemic effect of liposomal-entrapped calcitonin (CT) was evaluated in rats. Salmon CT and human CT were entrapped in liposomes composed of egg phosphatidylcholine with or without an equimolar amount of cholesterol. The liposomes were separated by Sepharose 4B chromatography into fractions consisting of large multilamellar vesicles and small unilamellar vesicles. The incorporation of CT was monitored by counting [125I]CT and by specific RIA. Liposomal entrapment enhanced the hypocalcemic potency of parenterally administered salmon CT and human CT. After iv administration, the large multilamellar vesicles were more potent than small unilamellar vesicles in their hypocalcemic effect; cholesterol inclusion in the MLV liposome preparation prolonged the hypocalcemia. However, with im administration, the cholesterol-free liposomes were more potent than their cholesterol-containing counterparts regardless of size. These studies demonstrate that liposomal entrapment can be used to enhance the hypocalcemic potency of CT. It appears that both the size and composition of the liposome preparation are important in this effect, as is the route of administration. It may be possible to produce liposome-CT preparations with advantageous pharmacological characteristics.

Preclinical safety evaluation of the nadolol/bendroflumethiazide combination in mice, rats, and dogs

Nadolol, a beta-adrenergic antagonist, and bendroflumethiazide, a thiazide diuretic, were administered orally alone and in combination to animals in acute and 6-month toxicity studies and in a rat teratology study. The two drugs in combination showed no evidence of potentiation of acute toxicity in mice. Nadolol and/or bendroflumethiazide were administered orally to rats at daily doses of 1000 or 160 mg/kg of nadolol and 125 or 20 mg/kg of bendroflumethiazide and to dogs at daily doses of 160 or 40 mg/kg of nadolol and 20 or 5 mg/kg of bendroflumethiazide for 6 months. The two drugs, alone and in combination, caused only minor changes in clinical-laboratory tests and no major gross or histopathologic changes. Many of the changes noted were expected pharmacologic effects of the individual agents. The drugs, alone or in combination, produced no evidence of embryotoxicity, fetotoxicity, or teratogenicity in rats. The results of these studies indicate that nadolol and bendroflumethiazide have a low order of toxicity individually, and when given in combination show no additional or potentiated toxicity.