Purification and renaturation of recombinant human lymphotoxin (tumour necrosis factor beta) expressed in Escherichia coli as inclusion bodies

High level expression of recombinant human tumour necrosis factor beta (rhTNF-beta) in Escherichia coli results in the formation of two portions of protein, namely soluble active protein and insoluble protein which is inactive and aggregates in the form of inclusion bodies (IBs). In this study, a procedure for purification and renaturation of rhTNF-beta from inclusion bodies has been designed and verified experimentally with a product purity of more than 90% and a recovery of about 30%. The procedure includes washing of IBs with specific wash buffer (Triton X-100/EDTA/lysozyme/PMSF), their solubilization with 8 mol dm-3 alkaline urea, purification with ion-exchange columns, refolding with renaturation buffer and finally concentration and desalination with an ultrafiltration membrane. The characteristics of the renatured protein were identical with those of purified protein from the soluble fraction as demonstrated by (1) SDS-PAGE, (2) cytotoxic activity on mouse L929 cells, (3) N-terminal amino acid sequence, and (4) gel filtration chromatography.

Importance of tonicity of carbicarb on the functional and metabolic responses of the acidotic isolated heart

In this study, the physiological and metabolic effects of Carbicarb administered as an isotonic (150 mmol/L Na[n[]I+) or hypertonic (1 mol/L Na[n[]I+) solution over 2 minutes in the acidotic isolated heart were compared. Physiological monitoring as well as 31P and 23Na nuclear magnetic resonance spectroscopy were performed. Both isotonic and hypertonic Carbicarb induced comparable dose-dependent increases in intracellular pH as well as decreases in inorganic phosphate and increases in creatine phosphate concentrations, which were sustained for 20 minutes. However, immediate functional improvement was greater in hearts receiving isotonic Carbicarb. Metabolic acidosis conditions resulted in a 27% increase in cytosolic sodium by 30 minutes (P < .05). In this setting, hypertonic Carbicarb induced a large transient increase in cytosolic sodium, whereas isotonic Carbicarb caused immediate and sustained decreases in cytosolic sodium. These data suggest that isotonic Carbicarb may have more beneficial effects on cardiac function than hypertonic Carbicarb. These effects may be related to associated changes in cytosolic sodium.

Autumn southward 'return' migration of the mosquito Culex tritaeniorhynchus in China

Direct evidence for a southward 'return' migration in autumn of the mosquito Culex tritaeniorhynchus in China was obtained by aerial sampling with a net suspended from a balloon. In a preliminary study between 2 and 20 September 1990 at Jiangpu, near Nanjing, in Jiangsu Province, 11 females and 4 males of this species were taken at heights of 150-250 m. During 17-26 October 1991 at Dongxiang in northern Jiangxi Province, 44 mosquitoes (8 males, 36 females) were caught in the aerial net at heights of 80-380 m in northeasterly winds (E-NNW). Most of the specimens were flying within the subsiding air-mass behind a cold front. Cx tritaeniorhynchus was the only species identified (31 females) among the mosquitoes from Dongxiang. Of 24 females dissected, 17 had N stage ovaries--interpreted as diapause, five had stage I ovaries, one had stage II ovaries, and one was gravid (stage V), but none was freshly blood-fed. Cx tritaeniorhynchus is the main vector of Japanese viral encephalitis in China, and it is possible that the virus is reintroduced to northern temperate areas in spring by northward migration of infected Cx tritaeniorhynchus females.

Non-viral sequences at the 5' ends of Dugbe nairovirus S mRNAs

Analyses of the mRNA transcription processes of viruses in four genera (Bunyavirus, Hantavirus, Phlebovirus and Tospovirus) of the family Bunyaviridae have revealed a common mechanism of initiation using host-derived primers, known as cap-snatching. To provide similar information on the fifth genus in the family, the 5' ends of Dugbe nairovirus S mRNA species were specifically cloned and sequenced. This revealed the presence of non-viral heterogeneous sequences, five to 16 nucleotides in length (average of 10 nucleotides) at the 5' ends, confirming that cap-snatching to prime mRNA synthesis is a familial characteristic of the Bunyaviridae. Inspection of the sequences in the primers on nairovirus, bunyavirus and phlebovirus mRNAs suggests that in some cases polymerase slippage occurs shortly after initiation, resulting in a partial reiteration of the 5'-terminal nucleotides of the viral RNA.

The involvement of the cytoskeleton in regulating IP3 receptor-mediated internal Ca2+ release in human blood platelets

In this study we have used saponin to permeabilize platelet membranes in order to test directly the involvement of IP3 in regulating internal Ca2+ release, and to measure IP3 binding to its receptor. Our results indicate that platelet vesicles release Ca2+ as early as 3 seconds after IP3 addition. Using [3H]IP3, we have found that platelets contain a single class of high affinity IP3 binding sites with a Kd of approximately 0.20 (+/- 0.01) nM. Immuno-blotting shows that platelets contain a 260 kDa polypeptide which shares immunological cross reactivity with brain IP3 receptor. Immunofluorescence staining data indicate that the IP3 receptor is preferentially located at the periphery of the platelet plasma membrane. Most importantly, both IP3 binding and IP3-induced Ca2+ release activities are significantly inhibited by cytochalasin D (a microfilament inhibitor) and colchicine (a microtubule inhibitor). These findings suggest that the cytoskeleton is involved in the regulation of IP3 binding and IP3 receptor-mediated Ca2+ release during platelet activation.

A physiological role of peptide YY on exocrine pancreatic secretion in rats

BACKGROUND

Peptide YY (PYY) given intravenously was shown to inhibit pancreatic exocrine secretion both in the dog and the rat. However, a possible physiological role of PYY on the pancreatic secretion has not been clarified. The present study was undertaken to investigate its physiological role on the exocrine pancreas.

METHODS

In conscious rats, plasma PYY was determined in response to oral ingestion of a 6-mL meal and intravenous infusion of PYY; small intestinal transit time was measured by phenol red as a nonabsorbable marker, and pancreatic secretory studies were performed in rats with pancreatic fistulas and jugular vein catheters.

RESULTS

Oral ingestion of the meal (containing phenol red, 1.6 mg/100 mL) significantly increased plasma PYY within 30 minutes. During this period, most (97%) of the phenol red was detected in the proximal two-thirds of the small intestine. Intravenous infusion of PYY in 25, 50, and 100 pmol.kg-1 x h-1 produced a dose-dependent increase in plasma PYY. The dose of PYY that simulated the peak postprandial level was 50 pmol.kg-1 x h-1, and this dose of PYY significantly inhibited the pancreatic secretion stimulated by physiological doses of secretin and cholecystokinin-8 (CCK-8). After the meal, pancreatic secretion of bicarbonate and protein significantly increased in rats pretreated with normal rabbit serum, whereas this increase was significantly augmented in rats pretreated with an anti-PYY serum because the postprandial increase in plasma PYY was abolished.

CONCLUSIONS

PYY plays a regulatory role in the postprandial pancreatic exocrine secretion in rats.

Effect of the rice bran-derived phytosterol cycloartenol ferulic acid ester on the central nervous system

In order to investigate the effect of cycloartenol ferulic acid ester (CFE, CAS 21238-33-5), a component of gamma-oryzanol which is a phytosterol derived from rice bran, on the central nervous system, a variety of pharmacological tests were performed. It was shown that CFE had a suppressant effect on the central nervous system, but its properties were different from those of existing major and minor tranquilizers. In addition, its efficacy in several models of cerebral dysfunction was demonstrated. Since any clear effects could not be obtained under the treatments with gamma-oryzanol, CFE seems to be more useful than gamma-oryzanol. Thus the results of this study suggest that CFE may serve as a new plant-derived cerebral activator possessing a wide range of pharmacological actions.

The involvement of ankyrin in the regulation of inositol 1,4,5-trisphosphate receptor-mediated internal Ca2+ release from Ca2+ storage vesicles in mouse T-lymphoma cells

Mouse T-lymphoma cells contain a unique type of internal vesicle which bands at the relatively light density of 1.07 g/cc. These vesicles do not contain any detectable Golgi, endoplasmic reticulum, plasma membrane, or lysosomal marker protein activities. Binding of [3H]inositol 1,4,5-trisphosphate (IP3) to these internal vesicles reveals the presence of a single, high affinity class of IP3 receptor with a dissociation constant (Kd) of 1.6 +/- 0.3 nM. Using a panel of monoclonal and polyclonal antibodies against IP3 receptor, we have established that the IP3 receptor (approximately 260 kDa) displays immunological cross-reactivity with the rat brain IP3 receptor. Polymerase chain reaction analysis of first-strand cDNAs from both mouse T-lymphoma cells and rat brain tissues reveals that the IP3 receptor transcript in mouse T-lymphoma cells belongs to the short form (non-neuronal form) and not the long form (neuronal form) detected in rat brain tissue. Scatchard plot analysis shows that high affinity binding occurs between ankyrin and the IP3 receptor with a Kd of 0.2 nM. Most importantly, the binding of ankyrin to the light density vesicles significantly inhibits IP3 binding and IP3-induced internal Ca2+ release. These findings suggest that the cytoskeleton plays a pivotal role in the regulation of IP3 receptor-mediated internal Ca2+ release during lymphocyte activation.

Decreased synthesis and delayed processing of sulfated glycoproteins by cells from human polycystic kidneys

BACKGROUND

In polycystic kidney disease, there is progressive distention of tubules and remodeling of an altered extracellular matrix. Recent findings indicate a defect(s) in the synthesis, post-translational modification, cellular transport, and extracellular matrix incorporation of proteoglycans in PKD that may have a fundamental role in its pathogenesis.

EXPERIMENTAL DESIGN

Pulse-chase techniques and quantitative autoradiography were used to investigate in vitro the de novo synthesis and the kinetics of intracellular transport and extracellular matrix assembly of sulfated glycoproteins by epithelial cells from normal human kidneys (NK) and from cysts of autosomal dominant polycystic kidneys (ADPKD). NK and ADPKD cell monolayers were pulsed with [35S]sulfate for 150 min and chased for four intervals between 15 and 120 min.

RESULTS

In ADPKD versus NK cells there was a significant reduction in the de novo synthesis of sulfated glycoproteins and, during the chase, a marked prolongation of the disappearance time for cellular sulfated glycoproteins. Transport kinetics revealed a substantial delay in processing and release of these macromolecules by the Golgi apparatus in ADPKD cells. During the chase, kinetics for the cellular transport of sulfated glycoproteins by secretory vesicles and their assembly into extracellular matrix were comparable in ADPKD and NK cells. However, the percentage of total sulfated glycoproteins incorporated into the matrix of ADPKD versus NK cell monolayers was notably diminished.

CONCLUSIONS

The findings indicate that in ADPKD versus NK cell monolayers, synthesis of sulfated glycoproteins is impaired, processing of sulfated glycoproteins by the Golgi apparatus is prolonged, and assembly of these macromolecules into the extracellular matrix is reduced. These alterations may have a fundamental role in the pathogenesis of autosomal dominant polycystic kidney disease.

Characterization of Bunyamwera virus S RNA that is transcribed and replicated by the L protein expressed from recombinant vaccinia virus

Analysis of the 5' termini of Bunyamwera virus S segment mRNAs by cloning and sequence analysis revealed the presence of nonviral, heterogeneous sequences 12 to 17 bases long. This is similar to reports for other members of the family Bunyaviridae and is taken to indicate that mRNA transcription is primed by a "cap-snatching" mechanism. The 3' end of the Bunyamwera virus S mRNA was mapped, by using an RNase protection assay, to 100 to 110 nucleotides upstream of the 3' end of the template. Previously we reported expression of the Bunyamwera virus L (polymerase) protein by recombinant vaccinia virus and demonstrated that the recombinant L protein was functional in terms of RNA synthesis activity in a nucleocapsid transfection assay (H. Jin and R. M. Elliott, J. Virol. 65: 4182-4189, 1991). In the present study we further analyze the RNAs made by using this system and show that positive-sense RNAs contain 5' nonviral sequences. Hence the initiation of mRNA transcription by the recombinant L protein resembles that seen during authentic bunyavirus infection and suggests that the L protein has the endonuclease activity which generates the primers. Some of these positive-sense transcripts terminated at the mRNA termination site, but the majority read through to the end of the template. No primer sequences were found at the 5' terminal of negative-sense RNAs. The recombinant L protein was able to replicate negative-sense RNA supplied by transfected virion-derived nucleocapsids, and both positive- and negative-sense RNAs were synthesized. These results indicate that the recombinant L protein has both transcriptase and replicase activities.

Immunocytochemical localization of substance P and neurofilament proteins in the guinea pig vestibular ganglion

To examine the cytochemical features of primary vestibular afferent neurons, we examined the immunocytochemical distribution of substance P(SP) and neurofilament proteins (NFP) in the guinea pig vestibular endorgans and ganglion. 84.9% of vestibular ganglion cells showed SP-like immunoreactivity. SP immunoreactive cells were small in diameter (25.4 microns), and randomly distributed in the ganglia. NFP immunoreactive cells (34.2%) were relatively large in diameter (31.1 microns). By double-staining immunocytochemistry it was possible to distinguish three different cell types: SP-positive/NFP-negative, SP-negative/NFP-positive, and SP/NFP-positive vestibular ganglion cells. Vestibular ganglion cells can thus be classified on the basis of size and immunocytochemical characteristics. These chemically distinct subpopulations of vestibular ganglion cells may be an indication of functional differences within vestibular afferent neurons.

Mesenchymal hamartoma of the liver: report of an adult case and review of the literature

A case of mesenchymal hamartoma of the liver incidentally found to be a hyperechoic mass by abdominal ultrasonography in a 62-year-old male is described. Computed tomography and magnetic resonance imaging of the liver confirmed the presence of a well-demarcated inhomogeneous mass in the left medial segment. Hepatic arteriography revealed the mass to be generally hypovascular. Histopathologic diagnosis of the resected specimen was a solid form of benign mesenchymal hamartoma, a rather rare lesion for the patient's age. Fifteen adult cases of hepatic mesenchymal hamartoma in the literature including the present case are reviewed.

Blocking hypothalamic AT1 receptors lowers blood pressure in salt-sensitive rats

Previous studies from our laboratory have shown that microinjection of DuP 753 (2-n-butyl-4-chloro-5-(hydroxymethyl)-1-[[2'-(1H-tetrazol-5-yl) biphenyl-4-yl]methyl]imidazole, potassium salt), a highly selective nonpeptide antagonist of type 1 angiotensin II receptors, into the anterior hypothalamic area produces a dose-related depressor response in salt-sensitive spontaneously hypertensive rats fed a basal (1%) salt diet. The current study tested the hypothesis that the depressor response to anterior hypothalamic type 1 angiotensin II receptor blockade with DuP 753 or its metabolite EXP 3174 is enhanced by high (8%) salt feeding in this model. DuP 753 or EXP 3174 (40 micrograms in 100 nl artificial cerebrospinal fluid vehicle) or vehicle alone was microinjected into the anterior hypothalamic area of conscious salt-sensitive spontaneously hypertensive and Wistar-Kyoto rats that had been fed 1% or 8% salt diets for 3 weeks. Both DuP 753 and EXP 3174 caused significant decreases in mean arterial pressure in spontaneously hypertensive but not in Wistar-Kyoto rats fed either diet. The magnitude and duration of the depressor responses to DuP 753 and EXP 3174 were significantly greater in the 8% salt-fed spontaneously hypertensive rats than in 1% salt-fed rats. Vehicle injections had no effect on blood pressure in either strain-diet group. Microinjection of angiotensin II (2 micrograms in 100 nl artificial cerebrospinal fluid vehicle) into the anterior hypothalamic area caused significant pressor and bradycardiac responses in all strain-diet groups; dietary salt supplementation enhanced these effects in salt-sensitive spontaneously hypertensive rats but not in Wistar-Kyoto rats. These responses were blocked by pretreatment with EXP 3174.(ABSTRACT TRUNCATED AT 250 WORDS)

Normobaric hypoxia stimulates endothelin-1 gene expression in the rat

The current study tested the hypothesis that exposure to hypoxia enhances endothelin-1 (ET-1) gene expression and elevates circulating ET-1 levels in the rat. Rats were exposed to normobaric hypoxia (10% O2) or room air for 24 or 48 h. ET-1 in arterial blood was measured by radioimmunoassay. ET-1 gene transcript levels were measured by the slot blot technique on total RNA isolated from lung, right and left atria, right and left ventricles, kidney, spleen, liver, brain, main trunk of pulmonary artery, and thoracic aorta. Blots were probed with a 0.5 kb rat prepro ET-1 cDNA that does not cross-hybridize with mRNA for ET-2 or ET-3. Plasma ET-1 levels were increased significantly at 24 (10.03 +/- 2.33 pg/ml) and 48 h (14.02 +/- 3.44 pg/ml) of hypoxia compared with air controls (4.14 +/- 0.66 pg/ml). ET-1 mRNA levels were increased significantly (2-fold) in lung and right atrium after 48 h of hypoxia; no change was seen in organs perfused by the systemic vascular bed. These findings suggest that the hypoxia-induced increase in circulating ET-1 levels is mainly of pulmonary origin. A paracrine effect of ET-1 produced by lung endothelial cells could account for hypoxic pulmonary hypertension.

A single amino-acid difference confers major pharmacological variation between human and rodent 5-HT1B receptors

Neuropsychiatric disorders such as anxiety, depression, migraine, vasospasm and epilepsy may involve different subtypes of the 5-hydroxytryptamine (5-HT) receptor. The 1B subtype, which has a unique pharmacology, was first identified in rodent brain. But a similar receptor could not be detected in human brain, suggesting the absence in man of a receptor with equivalent function. Recently a human receptor gene was isolated (designated 5-HT1B receptor, 5-HT1D beta receptor, or S12 receptor) which shares 93% identity of the deduced protein sequence with rodent 5-HT1B receptors. Although this receptor is identical to rodent 5-HT1B receptors in binding to 5-HT, it differs profoundly in binding to many drugs. Here we show that replacement of a single amino acid in the human receptor (threonine at residue 355) with a corresponding asparagine found in rodent 5-HT1B receptors renders the pharmacology of the receptors essentially identical. This demonstrates that the human gene does indeed encode a 1B receptor, which is likely to have the same biological functions as the rodent 5-HT1B receptor. In addition, these findings show that minute sequence differences between homologues of the same receptor from different species can cause large pharmacological variation. Thus, drug-receptor interactions should not be extrapolated from animal to human species without verification.

[The relationship between plasma atrial natriuretic peptide (ANP) and glomerular ANP receptors in 5/6 nephrectomized rats]

Chronic renal failure was induced in male Wistar rats with 5/6 nephrectomy (group I) and sham-operation was carried in the controls (group II). The results showed that in group I, plasma ANP levels increased progressively as Scr elevated. The plasma levels of renin and angiotensin raised simultaneously as compared with the controls (P < 0.001). At the 20th week after operation, urine volume and Na decreased significantly (P < 0.05) and the number of glomerular ANP receptors decreased significantly at the 12th week (P < 0.05) and 20th week (P < 0.01). Our data suggest that in 5/6 nephrectomized rats: 1. The elevation of plasma ANP level might be partly caused by damage of glomerular receptors. 2. The elevated plasma ANP could not cause its diuretic, natriuretic, blood pressure depression and R-A inhibition effect due to the damage of kidney ANP receptors.

Ganglion atrial natriuretic peptide in NaCl sensitive spontaneously hypertensive rats

Reports from other laboratories have shown that atrial natriuretic peptide (ANP) stores in sympathetic ganglia are increased during dietary NaCl supplementation in normotensive rats. We have previously demonstrated that dietary NaCl supplementation in NaCl sensitive spontaneously hypertensive rats (SHR-S) exacerbates hypertension and enhances peripheral sympathetic nervous system activity, while NaCl resistant Wistar-Kyoto (WKY) rats show neither response. Since endogenous ANP may inhibit ganglion transmission, an inability of SHR-S to increase ganglion ANP appropriately in response to high NaCl feeding could contribute to the NaCl induced increase in sympathetic nervous system activity and blood pressure in this model, while an increase in ganglion ANP in NaCl supplemented WKY would tend to prevent sympathetic activity and blood pressure from rising. The current study tested the hypothesis that ganglion ANP levels increase in WKY but not in SHR-S during dietary NaCl supplementation. Male SHR-S and WKY rats were placed on 1% or 8% NaCl diets at 7 weeks of age. The rats were decapitated without prior anesthesia 3 weeks later, and the superior cervical and celiac ganglia were removed for the measurement of ANP by radioimmunoassay. Dietary NaCl supplementation produced significant increases in blood pressure in SHR-S, but not in WKY rats; the high NaCl diet was associated with significant increases in the ANP content of superior cervical and celiac ganglia in WKY rats, but not in SHR-S.(ABSTRACT TRUNCATED AT 250 WORDS)

[A preliminary approach to pathological and biochemical changes of the lungs injured by domestic pingyangmycinum]

Two hundred male mice, weighing 18-24g, were randomized into four groups. A model of lung injury was established in mice by intratracheal administration of a single dose of domestic pingyangmycinum (Bleomycin A5). The dose-effect relationship for different doses of pingyangmycinum (0.05, 0.1, 0.2 mg) on the lung injury, and the change of hydroxyprolin (Hyp), ceruloplasmin (CP), angiotensin converting enzyme (ACE), superoxide dismutase (SOD) in mice were investigated. The results showed that the pathological changes of alveolitis and pulmonary interstitial fibrosis were more severe, and mortality of the mice was increased when pingyangmycinum dose was increased. During 2-6 weeks of this experiment, Hyp, CP, ACE and SOD in serum and Hyp in lung tissue were increased in different degrees. However, the activity of SOD in lung tissue was decreased. The possible mechanism of this lung injury is also discussed.

Mutagenesis of the L protein encoded by Bunyamwera virus and production of monospecific antibodies

Bacterial fusion proteins containing portions of the Bunyamwera virus L protein were used as immunogens to prepare antisera in rabbits. Of five fusion proteins injected into rabbits, three yielded sera that reacted with the Bunyamwera virus L protein, detected by Western blotting or immunoprecipitation. Two of these antisera were specific for either the amino- or carboxy-terminal regions of the L protein. The specificity of these antisera was confirmed by their pattern of reactivity with full-length and truncated forms of the L protein. Plasmids containing the L gene cDNA under control of a bacteriophage T7 promoter were transfected into CV-1 cells which had previously been infected with a recombinant vaccinia virus, vTF7-3, that expresses T7 RNA polymerase. Antigenically authentic L protein was expressed. Using a nucleocapsid transfection assay developed previously, we showed that the transiently expressed L protein had RNA synthesis activity. Site-specific mutations were made in the L cDNA-containing plasmid to change certain amino acids in the putative polymerase domain of the L protein. The effects of these amino acid substitutions on the RNA synthesis activity of the L protein were monitored using the nucleocapsid transfection assay. These experiments showed that residues strictly conserved between the L proteins of different viruses in the family Bunyaviridae were obligatorily required for activity, whereas non-conserved residues could be substituted without abolishing RNA synthesis capability. Our results provide direct evidence for the functional significance of particular amino acids in the polymerase domain of a negative-strand virus RNA polymerase.

Atrial natriuretic peptide modulates baroreceptor reflex in spontaneously hypertensive rat

Our previous studies have suggested that atrial natriuretic peptide in the caudal nucleus tractus solitarii is involved in the centrally mediated regulation of blood pressure in the salt-sensitive spontaneously hypertensive rat (SHR). The current study tested the hypothesis that endogenous atrial natriuretic peptide in the caudal nucleus tractus solitarii participates in baroreceptor reflex control of heart rate in this hypertensive model. Salt-sensitive SHR and control Wistar-Kyoto (WKY) rats maintained on basal (1%) salt intake were studied. Arterial baroreceptor reflex-mediated changes in heart rate were recorded in conscious unrestrained rats during phenylephrine (5-40 micrograms.kg-1.min-1 infusion; 30 minutes later, atrial natriuretic peptide (50 ng), monoclonal antibody to atrial natriuretic peptide (0.55 micrograms), purified mouse immunoglobulin G (0.55 micrograms), or artificial cerebrospinal fluid vehicle (50 nl) was microinjected into the caudal nucleus tractus solitarii. Phenylephrine infusion was then repeated and mean arterial pressure and heart rate were monitored as before. The slope of the heart rate/mean arterial pressure relation was significantly less (p less than 0.05) in the salt-sensitive SHR than in the WKY control, indicating that baroreceptor reflex control of heart rate was blunted in this hypertensive model. Microinjection of atrial natriuretic peptide into the caudal nucleus tractus solitarii further blunted (p less than 0.05) baroreceptor reflex control of heart rate in salt-sensitive SHR but not in WKY rats. In contrast, microinjection of the monoclonal antibody enhanced the sensitivity of baroreceptor reflex control of heart rate in salt-sensitive SHR but not in WKY rats.(ABSTRACT TRUNCATED AT 250 WORDS)

Salt supplementation does not alter the pressor effect of blocking atrial natriuretic peptide in nucleus tractus solitarii

We have previously shown that microinjection of monoclonal antibody to atrial natriuretic peptide (ANP) into the caudal nucleus tractus solitarii causes a pressor response in salt-sensitive spontaneously hypertensive rats (SHR) fed a basal (1%) salt diet, suggesting that endogenous ANP in this region may be involved in the centrally mediated regulation of blood pressure in this model. The present study tested the hypothesis that the pressor effect of blocking endogenous ANP in caudal nucleus tractus solitarii is enhanced by dietary salt supplementation in salt-sensitive SHR. Monoclonal antibody to ANP (0.55 micrograms) in 50 nl artificial cerebrospinal fluid or control immunoglobulin G was microinjected into the caudal nucleus tractus solitarii of conscious salt-sensitive SHR, salt-resistant SHR, and Wistar-Kyoto rats fed 1% or 8% salt diets for 3 weeks. Microinjection of the monoclonal antibody into the caudal nucleus tractus solitarii evoked similar increases in mean arterial pressure in salt-sensitive SHR on both 1% and 8% salt diets and in salt-resistant SHR on a 1% salt diet but had no effect in Wistar-Kyoto rats. In contrast, microinjection of control immunoglobulin G into this brain area did not alter mean arterial pressure or heart rate in any experimental group. Thus, endogenous ANP in caudal nucleus tractus solitarii mediates tonic control of blood pressure in both salt-sensitive and salt-resistant SHR but not in Wistar-Kyoto rats, and this effect is independent of the salt sensitivity of hypertension and of dietary salt intake.

Cicletanine blunts the pulmonary pressor response to acute hypoxia in rats

Cicletanine (CIC) recently has been shown to lower systemic arterial pressure in hypertensive animals and man by a mechanism that may involve potentiation of the vasodilator effect of atrial natriuretic peptide (ANP). We previously have shown that ANP prevents acute hypoxia-induced pulmonary vasoconstriction and modulates the severity of chronic hypoxic pulmonary hypertension. The current study tested the hypothesis that CIC inhibits the pulmonary pressor response to acute hypoxia by a cyclic guanosine monophosphate (cGMP)-dependent mechanism. Catheters were placed in the pulmonary arteries of Sprague-Dawley rats through the right jugular vein using a closed chest technique, and in the aorta through the right femoral artery. After a 24 hour recovery, CIC (600 mg/kg) or vehicle was administered orally by gavage to conscious rats 4 hours prior to exposure to 10% oxygen at ambient pressure or to room air. Mean pulmonary arterial pressure (MPAP) and mean systemic arterial pressure (MSAP) and heart rate (HR) were monitored for 3 hours. CIC attenuated the acute pulmonary pressor response to hypoxia (MPAP = 24.5 +/- 1.0 mm Hg in the "hypoxic+CIC" group vs. 29.9 +/- 1.0 mm Hg in the "hypoxic+vehicle" group; p less than 0.05 at 3 hours of hypoxic exposure), but had no significant effect on MSAP or HR. CIC had no effect on MPAP, MSAP, or HR in air control rats. Acute hypoxia caused significant increases in plasma ANP and cGMP and in kidney cGMP content, but CIC administration did not alter these parameters further. This is the first demonstration that acute administration of CIC attenuates the pulmonary pressor response to acute hypoxia in conscious rats.

Altered synthesis and intracellular transport of proteoglycans by cyst-derived cells from human polycystic kidneys

Employing in vitro pulse-chase techniques, we investigated the de novo synthesis and the kinetics of intracellular transport and extracellular matrix incorporation of proteoglycans (PG) by normal human renal epithelial cell and by epithelial cells isolated from cysts of autosomal dominant kidneys (ADPKD). Cell monolayers were pulsed either with (3H)leucine for 15 min and chased for seven intervals between 15 and 270 min or with (35S)sulfate for 150 min and chased for a single interval of 120 min. Total proteins and PG were isolated from cell, media, and matrix fractions and characterized by Sepharose CL-6B and DEAE-Sephacel chromatographies. ADPKD and NK cells synthesized comparable amounts of total proteins; however, the de novo synthesis of PG by ADPKD cells was significantly reduced. ADPKD versus NK cells exhibited a substantial delay in the cellular transport and extracellular release of de novo synthesized PG, indicating an impairment at the level of the Golgi complex and/or secretory vacuoles. PG synthesized by ADPKD versus NK cells had decreased charge density characteristics, probably due to a posttranslational defect in the sulfation of the PG glycosaminoglycan chains. ADPKD versus NK cells synthesized PG of higher molecular weight and had an increased proportion of chondroitin sulfate PG versus heparan sulfate PG. Collectively, these findings suggest a defect in the synthesis and intracellular transport of sulfated PG in human ADPKD cells.

Depressor effect of blocking angiotensin subtype 1 receptors in anterior hypothalamus

Previous studies have shown that the anterior hypothalamic area participates in the centrally mediated pressor response to exogenous angiotensin II. The current study was designed to test the hypothesis that endogenous anterior hypothalamic angiotensin II plays a significant role in blood pressure control. Type 1 angiotensin II receptors in the anterior hypothalamic area were blocked by local microinjection of DuP 753 (2-n-butyl-4-chloro-5-(hydroxymethyl)-1-[(2'-(1H-tetrazol-5-yl) biphenyl-4-yl)methyl]imidazole, potassium salt), a highly selective nonpeptide antagonist. DuP 753 (20 or 40 micrograms; in 100 nl artificial cerebrospinal fluid) or vehicle alone was microinjected into the anterior hypothalamic area of conscious NaCl-sensitive spontaneously hypertensive rats and Wistar-Kyoto controls. DuP 753 caused significant dose-related decreases in mean arterial pressure (maximal decrease, 22.5 +/- 1.8 mm Hg) with unchanged heart rate in NaCl-sensitive spontaneously hypertensive rats but effected no change in Wistar-Kyoto rats. Injections of equal volumes of artificial cerebrospinal fluid into the anterior hypothalamic area had no effect in either strain. Further, microinjection of DuP 753 into the posterior hypothalamic area produced no significant effect on blood pressure or heart rate in NaCl-sensitive spontaneously hypertensive rats. Microinjection into the anterior hypothalamic area of the selective type 2 angiotensin II receptor antagonist PD 123319 did not affect blood pressure or heart rate in NaCl-sensitive spontaneously hypertensive rats.(ABSTRACT TRUNCATED AT 250 WORDS)

[Isolation and identification of Leclercia adecarboxylate in clinical isolates in China]

1987, 3 strains of gram-negative straight rods were examined from 3 cases of patients with diarrhea. It's producing yellow pigment, fermentative metabolism of carbohydrates, oxidase test negative and motility with the help of peritrichous flagella. Through systematic biochemical identification, calculation of G+C mol% and homology of DNA/DNA, the species of Leclercia adecarboxylate are identified. While the susceptibility to certain antibiotics and the pathogenicity for white mice are tested, and relation of these microorganisms to clinical diarrhea is discussed.

Effects of acute and chronic blockade of neutral endopeptidase with Sch 34826 on NaCl-sensitive hypertension in spontaneously hypertensive rats

We have previously demonstrated that dietary NaCl supplementation is associated with increased circulating atrial natriuretic peptide (ANP) levels in Wistar-Kyoto (WKY) rats but not in spontaneously hypertensive rats (SHR), and that replacement with exogenous ANP prevents NaCl-sensitive hypertension in NaCl-sensitive SHR (SHR-S). The current study tested the hypothesis that chronic administration of the neutral endopeptidase (NEP) inhibitor Sch 34826 prevents NaCl sensitive hypertension in SHR-S by increasing endogenous ANP. Male SHR-S received Sch 34826 (90 mg/kg/day) or vehicle by gavage for 4 weeks beginning immediately before the initiation of 1% or 8% NaCl diets at age 7 weeks. Sch 34826 prevented the increase in arterial pressure in response to 8% NaCl in SHR-S, but had no effect on blood pressure in 1% NaCl fed SHR-S; plasma ANP levels were increased by 63 and 68% in the 1% and 8% NaCl groups, respectively, in response to Sch 34826. To examine the mechanism(s) of the antihypertensive effect of Sch 34826 in NaCl-supplemented SHR-S, a single dose (90 mg/kg) of Sch 34826 or vehicle was administered by gavage to SHR-S that had consumed 1% or 8% NaCl diets for 3 weeks. Sch 34826 abolished the NaCl-induced increase in blood pressure 3 h after treatment in 8% NaCl fed SHR-S, but had no effect in SHR-S fed the 1% NaCl diet. This effect was associated with increased urine volume and urinary sodium, ANP, and cyclic GMP in 8% NaCl fed SHR-S.(ABSTRACT TRUNCATED AT 250 WORDS)

Characterization of the human 5-hydroxytryptamine1B receptor

We report the cloning of a human gene encoding the 5-hydroxytryptamine1B receptor. The receptor has the characteristics of a G-protein-linked receptor and is most homologous to the human 5-HT1D receptor. This human 5-HT receptor gene, most abundantly expressed in striatum, is localized on chromosome 6, at 6q13, and the gene encoding the 5-HT1D receptor is localized on chromosome 1. Radioligand studies indicate that the affinity of [3H]5-HT is 16 +/- 2 nM. Drug competition studies indicate that the receptor displays high affinity (i.e. less than 40 nM) for 5-HT, 5-carboxyamidotryptamine, methiothepin, and metergoline.

[Immunohistochemical studies on the guinea pig's vestibular ganglion cell--with reference to the distribution of substance P and neurofilament]

The immunocytochemical distribution and morphological characteristics of substance P and neurofilament in vestibular end organs and the vestibular ganglion of the guinea pig were investigated. The effect of capsaicin on substance P-like immunoreactivity was also evaluated in this study. Substance P-like immunoreactivity was found in the peripheral region of vestibular end organs and in small or medium size vestibular ganglion cells. Approximately 85% of vestibular ganglion cells showed substance P-like immunoreactivity. Although substance P-like immunoreactivity was depleted in the nasal mucosa and trigeminal ganglion by capsaicin treatment, substance P distributed in the primary vestibular neurons was not affected. In contrast to the distribution of substance P, neurofilament was also found in the primary afferent neurons in the central regions of vestibular end organs. Neurofilament immunoreactive cells, which were larger in size than cells without neurofilament-like immunoreactivity comprised about 34% of vestibular ganglion cells. These immunocytochemical findings suggest that vestibular ganglion cells can be classified on the basis of size and immunocytochemical characteristics.

Comparative observation of the changes in serum lipid peroxides influenced by the supplementation of vitamin E in burn patients and healthy controls

A microfluorescence analytical method was used to determine the contents of serum lipid peroxides and vitamin E in 35 severely burned patients, among whom 18 had been given vitamin E, and in 113 healthy blood donors. A comparative survey showed that the serum vitamin E decreased most significantly from days 6 to 8 postburn in both groups of burned patients, while the concomitant serum lipid peroxides increased significantly and reached a peak value. In control patients, the serum vitamin E levels were lower and lipid peroxides higher than those of healthy people (P less than 0.05) from days 20 to 22 postburn. At this time in the vitamin E-treated patients, the serum vitamin E levels increased and lipid peroxides decreased to the levels of healthy people (P greater than 0.05). Therefore, appropriate supplementation with vitamin E in burn patients is necessary.

Spontaneously hypertensive rat: lymphoid depression is age dependent and mediated via a mononuclear cell subpopulation

Immune dysfunction has been reported in spontaneously hypertensive rats (SHR), particularly in mature animals with established hypertension. The current study examined the time course of development of immune dysfunction and defined its cellular basis in male SHR and control normotensive Wistar-Kyoto rats (WKY). Mitogen-induced proliferative responses in lymphoid cells obtained from induced proliferative responses in lymphoid cells obtained from SHR thymus and spleen before (age 4 wk) and during the development of (ages 8 and 12 wk) hypertension and in age-matched normotensive WKY were monitored. A 50% reduction in concanavalin A (Con A)-induced proliferative responses was seen in SHR thymocytes compared with those of WKY at 12 wk only, suggesting differences in immature T-cell populations. Con A-induced T-cell proliferative responses in splenocytes also differed between strains: greatest (as much as 8-fold) decreases were found in 12-wk-old SHR. Similar findings were obtained in splenocytes stimulated with lipopolysaccharide (LPS), indicating differences in B-cell function. Mononuclear cells depleted of their adherent cell population were prepared from SHR and WKY at 12+ wk of age and assayed for their proliferative responses to LPS and Con A. The remaining nonadherent mononuclear cells of SHR had proliferative responses equal to or greater than those of WKY. Further, when SHR splenic mononuclear cells were allowed to adhere to plastic, and the adherent fraction was co-cultured with either SHR G-10 nonadherent or unfractionated SHR splenic mononuclear cells, proliferative responses were suppressed by as much as 88%.(ABSTRACT TRUNCATED AT 250 WORDS)

Human dopamine D5 receptor pseudogenes

Molecular cloning studies have now identified five structurally homologous genes encoding the biosynthesis of the human dopamine receptors, DRD1, DRD2, DRD3, DRD4, and DRD5. Two of these dopamine receptors (DRD1 and DRD5) are encoded by intronless genes. To ascertain whether there are other intronless genes that share identity with the gene (DRD5) encoding the DRD5 receptor, we used a cloning method based on the polymerase chain reaction (PCR). Human genomic DNA was amplified by PCR with oligodeoxyribonucleotides (oligos) based on the DRD5 nucleotide (nt) sequence. Amplification of nt sequences between these oligos allowed the isolation of two independent intronless genes that share identity with DRD5. The full-length clones have also been isolated by screening human genomic libraries. The deduced amino acid sequences for these genes, PG-1 and PG-2, share 91% and 92% identity to DRD5, respectively. However, each of the genes contains differences in the coding regions that would render these genes incapable of encoding functional receptors. Thus, the human genome contains at least two DRD5 pseudogenes, consistent with in situ human chromosomal hybridization analysis which reveals the presence of two pseudogenes.

[A study on the inhibition effect of tetrandrine on the pingyangmycinum induced pulmonary fibrosis]

A model of pulmonary fibrosis caused by a single intratracheal injection 0.1 mg pingyangmycinum in mice was reported. The effect of tetrandrine, a herbal powder, 50 mg/kg time, on the pathological development of pulmonary fibrosis, and the activity of superoxide dismutase (SOD), angiotensin converting enzyme (ACE), quantity of hydroxyproline (HYP) in this mice model were investigated. We also contrast tetrandrine with cortisol. The result showed that tetrandrine may inhibit the formation and development of pulmonary fibrosis. On the other hand, tetrandrine and cortisol may increase the activity of SOD of lung tissue, reduce the quantity of HYP of lung tissue and decrease the activity of serum ACE.

Atrial natriuretic peptide in acute hypoxia-induced pulmonary hypertension in rats

To test the hypothesis that exogenous atrial natriuretic peptide (ANP) prevents the acute pulmonary pressor response to hypoxia, ANP (20-micrograms/kg bolus followed by 1-microgram.kg-1.min-1 infusion) or vehicle was administered intravenously to conscious rats beginning 3 min before exposure to hypoxia or room air for 90 min. Exogenous ANP abolished the acute pulmonary pressor response to hypoxia in association with marked and parallel increases in plasma ANP and guanosine 5'-cyclic monophosphate (cGMP) and with a significant increase in lung cGMP content. To examine whether endogenous ANP modulates the acute pulmonary pressor response to hypoxia, rats were pretreated with a monoclonal antibody (Ab) to ANP and exposed to hypoxia. Mean pulmonary arterial pressure (MPAP) in the Ab-treated rats was not different from control over the first 6 h of hypoxic exposure. Thereafter, the Ab-treated group had significantly higher MPAP than control. Our data suggest that 1) exogenous ANP blocks the pulmonary pressor response to acute hypoxia via stimulation of cGMP accumulation in the pulmonary vasculature, and 2) endogenous ANP may modulate the subacute, but not acute, phase of hypoxic pulmonary hypertension.

Expression of functional Bunyamwera virus L protein by recombinant vaccinia viruses

A cDNA containing the complete coding sequence of the Bunyamwera virus (family Bunyaviridae) L genome segment has been constructed and cloned into two recombinant vaccinia virus expression systems. In the first, the L gene is under control of vaccinia virus P7.5 promoter; in the second, the L gene is under control of the bacteriophage T7 phi 10 promoter, and expression of the L gene requires coinfection with a second recombinant vaccinia virus which synthesizes T7 RNA polymerase. Both systems express a protein which is the same size as the Bunyamwera virus L protein and is recognized by a monospecific L antiserum. The expressed L protein was shown to be functional in synthesizing Bunyamwera virus RNA in a nucleocapsid transfection assay: recombinant vaccinia virus-infected cells were transfected with purified Bunyamwera virus nucleocapsids, and subsequently, total cellular RNA was analyzed by Northern (RNA) blotting. No Bunyamwera virus RNA was detected in control transfections, but in cells which had previously been infected with recombinant vaccinia viruses expressing the L protein, both positive- and negative-sense Bunyamwera virus S segment RNA was detected. The suitability of this system to delineate functional domains within the Bunyamwera virus L protein is discussed.

Localization of substance P-like immunoreactivity in guinea pig vestibular endorgans and the vestibular ganglion

The immunocytochemical distribution of substance P (SP) in guinea pig vestibular endorgans and the vestibular ganglion was investigated. Two kinds of SP-immunoreactive fibers were distinguished. Most were thick, and found around or beneath sensory hair cells. These SP-immunoreactive fibers were distributed predominantly on the slope of the crista and the peripheral region of the macula. By electron microscopy, we confirmed this type of SP-like immunoreactivity to be restricted within primary afferent neurons. Some vestibular ganglion cells also showed SP-like immunoreactivity, suggesting that SP is present in some primary afferent neurons, and is involved in afferent neurotransmission. The characteristic distribution of SP may indicate functional differences within each endorgan. The other group of immunoreactive nerve fibers, varicous thin fibers, could be found in the stroma of vestibular endorgans, nerve trunk, vestibular ganglion, and along blood vessels of the vestibular ganglion. These fibers may have a different origin, and have an influence on blood flow and certain other functions.

[Chemical constituents of the aerial parts of six species of Bupleurum genus medicinally used in south-west region of China]

The chemical constituents of the aerial parts of six species of Bupleurum genus (B. kunmingense, B. polyclonum, B. wenchuanense, B. longicaule var. franchetii, B. rockii and B. chaishoui) medicinally used in south-west region of China have been investigated with the results of obtaining eight flavonoid compounds and six triterpenoid saponins. The aglycones of these eight flavonoid compounds are quercetin and isorhamnetin, which are different from the aglycones of the flavonoid compounds isolated from the aerial parts of B. chinense, the official species in Chinese Pharmacopoeia. In the latter case, the aglycone is kaempferol. This difference may be of chemotaxonomic value in Bupleurum genus.

Relation between plasma atrial natriuretic peptide (ANP) and glomerular ANP receptors in 5/6 nephrectomized rats

Chronic renal failure (CRF) was induced in male wistar rats (Group I) by 5/6 nephrectomy and the sham-operated ones served as control (Group II). The results showed that in Group I, plasma atrial natriuretic peptide (ANP) levels increased progressively as the Scr was elevated. Plasma R-A rose simultaneously compared to the normal (P less than 0.001). At the 20th week after operation, urine volume and Na decreased significantly (P less than 0.05). The number of glomerular receptors decreased markedly at the 12th week (P less than 0.05) and 20th week (P less than 0.01). Our data suggest that in 5/6 nephrectomized rats, the elevation of plasma ANP level might be partly caused by the damage of glomerular ANP receptors, and the elevated plasma ANP could not play its role in diuresis, natriuresis, blood pressure depression and R-A inhibition as a result of the damage of kidney ANP receptors.

Atrial natriuretic peptide clearance receptor agonist lowers pulmonary pressure in hypoxic rats

We demonstrated previously that intravenous administration of exogenous atrial natriuretic peptide (ANP) lowers mean pulmonary arterial pressure (MPAP) in hypoxia-adapted rats. To test the hypothesis that endogenous ANP may also lower MPAP in this model, C-ANP-(4-23), a ring-deleted analogue of ANP that binds to the biologically silent ANP clearance receptor (C-ANP receptor) but not to the ANP biological receptor (B-ANP receptor), was administered intravenously as a bolus injection (10 micrograms/kg) followed by an infusion (1 micrograms.kg-1.min-1 for 60 min) to rats adapted to hypoxia (10% O2) for 4 wk and to air control rats. C-ANP-(4-23) significantly lowered MPAP in hypoxic rats but not in air controls. A statistically insignificant reduction in mean systemic arterial pressure was found in both groups after C-ANP-(4-23) administration. C-ANP-(4-23) significantly (two- to threefold) increased endogenous plasma ANP levels in both groups; the increase was not significantly different between groups. Both basal and post-C-ANP-(4-23) levels of plasma ANP were greater in hypoxia-adapted animals than in air controls; the C-ANP-induced increase in plasma ANP was not significantly different between groups. These results suggest that the endogenous ANP may modulate pulmonary vascular tone in rats with hypoxic pulmonary hypertension.

The prevalence of dementia and Alzheimer's disease in Shanghai, China: impact of age, gender, and education

We report the prevalence rates for dementia and Alzheimer's disease (AD) obtained from a probability sample survey of 5,055 noninstitutionalized older persons in Shanghai, China. A two-stage procedure was used for case finding and case identification. A Chinese version of the Mini-Mental State Examination was used to determine cases of possible dementia. Three different cutoff points on this mental status test were used depending on the respondent's level of education. Clinical evaluations, based on functional assessments and psychiatric interview, medical and neurological examinations, three standardized mental status tests, and a selected group of psychometric tests, were made in the second stage of the study to ascertain the clinical diagnosis of dementia and AD utilizing the Diagnostic and Statistical Manual for Mental Disorders, edition 3 and National Institute of Neurological and Communicative Disorders and Stroke-Alzheimer's Disease and Related Disorders Association criteria, respectively. The prevalence rate of dementia in persons 65 years and older was 4.6%. Clinically diagnosed AD accounted for 65% of the subjects with dementia. These findings indicate that the prevalence of dementia in Shanghai is very much higher than figures published earlier for China and Japan, and at the lower part of the range of values reported for community residents in the United States and other Western countries, but less than half of that reported in the recently published survey of the elderly in East Boston. Increasing age, gender (female), and low education are each highly significant and independent risk factors for dementia. One hypothesis to explain the increased prevalence in elderly women who had received no formal education invokes the possibility of an effect of early deprivation, perhaps lowering brain "reserve," allowing the symptoms of dementia to appear at an earlier date during disease progression.

Atrial natriuretic peptide attenuates the development of pulmonary hypertension in rats adapted to chronic hypoxia

To test the hypothesis that chronic infusion of atrial natriuretic peptide (ANP) instituted before hypoxic exposure attenuates the development of pulmonary hypertension in hypoxia adapted rats, ANP (0.2 and 1.0 microgram/h) or vehicle was administered intravenously via osmotic minipump for 4 wk beginning before exposure to 10% O2 or to room air. Low dose ANP increased plasma ANP levels by only 60% of vehicle controls after 4 wk and significantly decreased mean pulmonary arterial pressure (MPAP) (P less than 0.01), the ratio of right ventricular weight to body weight (RV/BW) (P less than 0.01), and the wall thickness of small (50-100 microns) pulmonary arteries (P = 0.01) in hypoxia-adapted rats. ANP did not alter any of these parameters in air-control rats. High dose ANP increased plasma ANP levels by 230% of control and produced greater reductions in MPAP (P less than 0.001) and RV/BW) (P less than 0.05), but not in pulmonary arterial wall thickness, than the low dose. Neither dose of ANP altered mean systemic arterial pressure in either hypoxic or normoxic rats. The data demonstrate that chronic infusion of exogenous ANP at a dose that does not affect MPAP or RV weight in air-control rats attenuates the development of pulmonary hypertension and RV enlargement in rats adapted to chronic hypoxia.

Cross-cultural studies of dementia: use of a Chinese version of the Blessed-Roth Information-Memory-Concentration test in a Shanghai dementia survey

A culturally adapted Chinese version of the Blessed-Roth Information-Memory-Concentration test (CIMC) was used in a dementia screening survey of a probability sample of 5,055 elderly Shanghai residents. The individual items on the CIMC that best predicted the overall score were similar to the best predictor of an American version of the IMC. Performance on the CIMC was markedly affected by the level of education or lack thereof. In a subsample for whom clinical diagnoses were obtained, it was possible to establish cutoff values on the CIMC by stratifying the sample according to education.

Partial agonist activity of celiprolol as assessed in conscious unrestrained dogs in comparison with those of pindolol and labetalol

The effects of celiprolol on the heart rate (HR) and the total peripheral resistance (TPR) were studied in chronically instrumented conscious dogs in comparison with those of pindolol, propranolol and labetalol. Intravenous injection of pindolol, celiprolol and labetalol increased the HR and decreased the TPR dose-dependently, whereas propranolol did not. The ratios of doses that elicited 12% changes in both parameters (HR12/TPR12) were 4.85 +/- 2.63, 0.61 +/- 0.03 and 0.42 +/- 0.11 for celiprolol, pindolol and labetalol, respectively, indicating the preferential reduction of TPR by celiprolol. Changes in HR and TPR produced by these three agents were antagonized by propranolol dose-dependently. However, inhibition by 3 mg/kg of propranolol was incomplete in the cases of labetalol-induced decrease in the TPR at the dose of TPR12 (51%) and celiprolol-induced increase in the HR at the dose of HR12 (89%). These results suggest that changes produced by celiprolol as well as pindolol and labetalol were mostly explainable by partial agonist activity via beta-adrenoceptors. However, the contribution of the alpha-blocking activity must also be taken into consideration in the case of the reduction of the TPR by labetalol. In addition, there is a possibility that celiprolol may increase HR via its direct action.