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Receptor selectivity of natriuretic peptide family, atrial natriuretic peptide, brain natriuretic peptide, and C-type natriuretic peptide.

To elucidate the ligand-receptor relationship of the natriuretic peptide system, which comprises at least three endogenous ligands, atrial natriuretic peptide (ANP), brain natriuretic peptide (BNP), and C-type natriuretic peptide (CNP), and three receptors, the ANP-A receptor or guanylate cyclase-A (GC-A), the ANP-B receptor or guanylate cyclase-B (GC-B), and the clearance receptor (C-receptor), we characterized the receptor preparations from human, bovine, and rat tissues and cultured cells with the aid of the binding assay, Northern blot technique, and the cGMP production method. Using these receptor preparations, we examined the binding affinities of ANP, BNP, and CNP for the C-receptor and their potencies for cGMP production via the ANP-A receptor (GC-A) and the ANP-B receptor (GC-B). These analyses revealed the presence of a marked species difference in the receptor selectivity of the natriuretic peptide family, especially among BNPs. Therefore, we investigated the receptor selectivity of the natriuretic peptide family using the homologous assay system with endogenous ligands and receptors of the same species. The rank order of binding affinity for the C-receptor was ANP greater than CNP greater than BNP in both humans and rats. The rank order of potency for cGMP production via the ANP-A receptor (GC-A) was ANP greater than or equal to BNP much greater than CNP, but that via the ANP-B receptor (GC-B) was CNP greater than ANP greater than or equal to BNP. These findings on the receptor selectivity of the natriuretic peptide family provide a new insight into the understanding of the physiological and clinical implications of the natriuretic peptide system.

Animals

The isolation, characterization and partial sequence of a peptide rich in glutamic acid and aspartic acid (HGA-2 peptide) from calf thymus non-histone chromosomal protein HMG 2. Comparison with a similar peptide (HGA-1 peptide) from calf thymus non-histone chromosomal protein HMG 1.

A 41-residue peptide (HGA-2) containing a continuous sequence of 35 glutamic and aspartic residues was isolated from non-histone chromosomal protein HMG 2. This highly acidic peptide is compared with a similar peptide (HGA-1) isolated from non-histone chromosomal protein HMG 1.

Amino Acid Sequence

Brain natriuretic peptide as a novel cardiac hormone in humans. Evidence for an exquisite dual natriuretic peptide system, atrial natriuretic peptide and brain natriuretic peptide.

Using a specific radioimmunoassay for human brain natriuretic peptide (hBNP) with a monoclonal antibody, we have investigated its synthesis, secretion, and clearance in comparison with those of atrial natriuretic peptide (ANP) in normal subjects and patients with congestive heart failure (CHF). Mean BNP-like immunoreactivity (-LI) levels in normal atrium and ventricle were 250 and 18 pmol/g, respectively. The plasma BNP-LI level in normal subjects was 0.90 +/- 0.07 fmol/ml, which was 16% of the ANP-LI level. In contrast, the plasma BNP-LI level markedly increased in patients with CHF in proportion to its severity, and surpassed the ANP-LI level in severe cases. There was a significant step-up of the plasma BNP-LI level in the coronary sinus (CS) compared with that in the aortic root (Ao) and the difference between these BNP-LI levels, delta(CS-Ao)BNP, also increased with the severity of CHF. In addition, the step-up of the BNP-LI level in the anterior interventricular vein [delta(AIV-Ao)BNP] was comparable to delta(CS-Ao)BNP, indicating that BNP is secreted mainly from the ventricle. Predominant BNP synthesis in the ventricle was also confirmed by Northern blot analysis. Catheterization and pharmacokinetic studies revealed that hBNP is cleared from the circulation more slowly than alpha-hANP; this was in part attributed to lower (about 7%) binding affinity of hBNP to clearance receptors than that of alpha-hANP. A predominant molecular form of BNP-LI in the heart and plasma was a 3-kD form corresponding to hBNP. These results indicate that BNP is a novel cardiac hormone secreted predominantly from the ventricle, and that the synthesis, secretion and clearance of BNP differ from those of ANP, suggesting discrete physiological and pathophysiological roles of BNP in a dual natriuretic peptide system.

Antibodies, Monoclonal

Chemically unambiguous peptide immunogen: preparation, orientation and antigenicity of purified peptide conjugated to the multiple antigen peptide system.

We described a novel and simple approach to prepare chemically unambiguous peptide immunogen using the multiple antigen peptide (MAP) approach. This approach requires the conjugation of two purified components: a chloroacetylated oligomeric lysine core matrix and a synthetic peptide containing cysteine at either the carboxyl or amino terminus. The resulting MAP is structurally unambiguous and contains a quantifiable amount of peptide antigens. Furthermore, this method also provides a flexible strategy to link a peptide antigen to the core matrix at the desirable orientation to mimic the native molecule. The carboxyl fragment 43-50 of human transforming growth factor alpha (TGF alpha) was used as a test model for this approach. Antipeptide antibodies did not recognize the "reverse immunogen" in which the peptide was attached to the MAP core matrix at a reverse orientation. To determine the specificity of the antibodies, we used two series of point-substituted TGF alpha analogs containing either alanine or the corresponding D-amino acid replacement to map the antigenic site. The alanine analogs were used to determine the contribution of the side chain while the D-amino acid analogs were used to determine the importance of backbone conformation. The antigen site was found to consist of four residues (Asp47-Leu48-Leu49-Ala50) at the distal end of the peptide-MAP conjugate. The results provide a clear explanation for the specificity of the antipeptide antibodies and their failure to recognize the "reverse immunogen" since the distal and the flexible end of the peptide-MAP construct constitutes the antigenic site. Furthermore, our results also suggests a strategy of placing the antigenic portion of a short-peptide at the distal end in the MAP approach to prepare immunogen.

Amino Acid Sequence

The neurotransmitter role of calcitonin gene-related peptide in the rat and guinea-pig ureter: effect of a calcitonin gene-related peptide antagonist and species-related differences in the action of omega conotoxin on calcitonin gene-related peptide release from primary afferents.

In the rat and guinea-pig isolated ureter electrical field stimulation of intrinsic nerves (10 Hz for 10 s) produces transient inhibition of evoked (20 mM KCl or 0.1-1 microM neurokinin A) rhythmic contractions by releasing transmitter(s) from peripheral endings of capsaicin-sensitive primary afferents. The C-terminal fragment of human calcitonin gene-related peptide (8-37) blocked the inhibitory effect of electrical field stimulation as well as that produced by exogenous calcitonin gene-related peptide, while leaving unaffected the inhibitory response to isoprenaline. Human calcitonin gene-related peptide (8-37) was devoid of any inhibitory activity of its own but enhanced the amplitude and frequency of KCl-evoked rhythmic contractions in the rat ureter, probably by antagonizing the inhibitory effect of endogenous calcitonin gene-related peptide released by KCl. Omega conotoxin fraction GVIA, a peptide which possesses a potent blocking activity of N-type voltage-sensitive calcium channels, prevented the inhibitory response to electrical stimulation in the guinea-pig ureter, while leaving the response unaffected in the rat ureter. Conotoxin had no effect toward the inhibition produced by exogenous calcitonin gene-related peptide indicating its prejunctional site of action, demonstrated previously in the guinea-pig ureter [Maggi et al. (1990) Neurosci, Lett. 114, 203-206]. Dermorphin, an amphibian peptide with potent agonist activity on mu-type opioid receptors, inhibited the response to electrical stimulation in the guinea-pig ureter but had no effect in the rat ureter.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals

Protected natural peptides as intermediates for preparing semisynthetic peptides and protein analogs. Selective acylation of epsilon-amino groups in cyanogen bromide peptides of cytochrome c using azidoformates.

Treatment of CNBr peptides 66--80, 81--104 and 66--104 from cytochrome c with t-butyloxycarbonyl azide leads to selective acylation of the epsilon-amino groups of lysine residues and the phenolic hydroxyl groups of tyrosine residues with less than 25% acylation of the alpha-amino groups. Similar selectivity was obtained for reactions of benzyloxycarbonyl azide, p-nitrobenzyloxycarbonyl azide and p-methoxybenzyloxycarbonyl azide with peptide 81--104. All of these protective groups can be removed under mild conditions, and thus, the partially protected natural peptides are desirable intermediates for the preparation of semisynthetic peptides. Model condensation reactions of N alpha t-butyloxycarbonyl methionine N-hydroxysuccinimide ester with Z-protected peptide 81--104 produced a peptide corresponding to residues 80 to 104 of cytochrome c in 94% yield.

Acylation

Aplysia peptide neurotransmitters beta-bag cell peptide, Phe-Met-Arg-Phe-amide, and small cardioexcitatory peptide B are rapidly degraded by a leucine aminopeptidase-like activity in hemolymph.

We have been investigating the role of proteolytic enzymes in the inactivation of peptide neurotransmitters in the marine snail Aplysia. Previous studies (Squire, C. R., Talebian, M., Menon, J. G., Dekruyff, S. D., Lee, T. D., Shively, J. E., and Rothman, B. S. (1991) J. Biol. Chem. 266, 22355-22363) showed that neuroactive fragments of the neurotransmitter alpha-bag cell peptide (alpha-BCP) were rapidly degraded (t1/2 = 0.5-2.7 min) in plasma, hemolymph that had been cleared by centrifugation. Degradation was caused by one or more enzymes resembling mammalian leucine amino-peptidase (LAP, EC 3.4.11.1). In this report we show that three other Aplysia peptide neurotransmitters, beta-BCP(1-5) (Arg-Leu-Arg-Phe-His), FMRFa (Phe-Met-Arg-Phe-amide), and SCPB(1-9) (Met-Asn-Tyr-Leu-Ala-Phe-Pro-Arg-Met-amide) are rapidly degraded (t1/2 = 0.3-2.4 min) in plasma by apparently the same LAP-like enzyme(s). Our findings strongly suggest that the LAP-like enzyme(s), by means of its broad substrate specificity and access to the extracellular spaces of the nervous system in vivo, plays a significant role in the inactivation of many Aplysia peptide neurotransmitters, and they raise the possibility that proteolytic enzymes in the extracellular fluid contribute significantly to the inactivation of peptide neurotransmitters in other animal species.

Amino Acid Sequence

Bee venom peptides XVIII. Peptide-m and mcd-peptide: Isolation and characterization.

A simple method is described for the purification of peptide-M and MCD-peptide from bee venom. The steps are Sephadex G-50 gel filtration of pH 4.5 (Steps 1 and 2) and chromatography on silica gel (Steps 3 and 4). The peptides are homo geneous with respect to thin-layer chromatography, electrophoresis at pH 2.0, and amino acid analysis. Peptide-M contains 24 amino acid residues and has a calculated molecular weight of 2750.

Amino Acids

[Basic peptides in bee venom, III. Synthesis of peptide fragments from the sequence of the mast-cell-degranulating peptide (author's transl)].

The synthesis by conventional methods of the following three peptides is described: MCD(8-11) Boc-His(Trt)-Val-Ile-Lys(Z) (III) MCD(5-7) Boc-Cys(SiPr)-Lys(Z)-Arg(Tos) (IV) and MCD(1-4) Boc-Ile-Lys(Z)-Cys(Trt)-Asn(Mbh) (V). These peptides are fragments of the mast cell degranulating peptide from bee venom. The purity of the fragments synthesized was examined by thin-layer chromatography, amino acid and elementary analysis. Including the fragments Boc-Lys(Z)-Ile-Cys(SiPr)-Gly-Lys(Z) (I) and Boc-Pro-His(Trt)-Ile-Cys(Trt)-Arg(Tos) (II), which were described earlier, the synthesis of the mast-cell-degranulating peptide on a polyethylene-asparagine support appears possible.

Amino Acid Sequence

Pituitary adenylate cyclase-activating peptide (PACAP), a new vasoactive intestinal peptide (VIP)-like peptide in the respiratory tract.

Pituitary adenylate cyclase-activating peptide (PACAP) is a vasoactive intestinal peptide (VIP)-like peptide recently isolated from ovine hypothalami. Nerve fibers displaying PACAP immunoreactivity were found in the respiratory tract of rats, guinea pigs, ferrets, pigs, sheep and squirrel monkeys. A moderate supply of PACAP-immunoreactive fibers was seen in the nasal mucosa of guinea pigs. Few to moderate numbers of PACAP-containing fibers occurred in the tracheo-bronchial wall of rats, guinea pigs, ferrets, pigs, sheep and squirrel monkeys. The fibers were distributed beneath the epithelium, around blood vessels and seromucous glands, and among bundles of smooth muscle. In the lungs, the immunoreactive fibers were observed close to small bronchioli. A few PACAP-immunoreactive nerve cell bodies were seen in the sphenopalatine and otic ganglia of guinea pigs. Simultaneous double immunostaining of the respiratory tract of sheep and ferrets revealed that all PACAP-containing nerve fibers stored VIP. We suggest that neuronal PACAP may take part in the regulation of smooth muscle tone and glandular secretion.

Animals

Regulation of intestinal proglucagon-derived peptide secretion by intestinal regulatory peptides.

The physiological regulation of intestinal proglucagon-derived peptide secretion has not been well studied. We have therefore used a fetal rat intestinal cell culture model to investigate the control of secretion of the gut glucagon-like immunoreactive (GLI) peptides by other intestinal regulatory peptides in vitro. Secretion of the intestinal GLI peptides was found to be stimulated in a dose-dependent fashion by the intestinal endocrine peptide, gastric inhibitory peptide (at greater than or equal to 10(-10) M, P less than 0.05), and by the neurocrine peptides, gastrin-releasing peptide (at greater than or equal to 10(-12) M, P less than 0.05), and calcitonin gene-related peptide (at greater than or equal to 10(-8) M, P less than 0.05). Gastrin-releasing peptide and its amphibian equivalent, bombesin were equipotent in stimulating GLI peptide secretion. In contrast, the endocrine and neurocrine intestinal somatostatin-related peptides, somatostatin-28 and -14, inhibited release of the GLI peptides, at concentrations of 10(-10) (P less than 0.01) and 10(-8) (P less than 0.01) M, respectively, with significant differences in potency between the two peptides detected at 10(-10) M (P less than 0.05). The inhibitory effects of both somatostatin-28 and -14 could be blocked by preincubation of the cells with pertussis toxin (P less than 0.05). Dose-dependent stimulation of gut GLI peptide secretion was also detected in response to treatment of cultured cells with sodium oleate (at 10(-4) M; P less than 0.05), or with the cholinergic agonist bethanecol (at greater than or equal to 100 microM; P less than 0.05). Other endocrine [cholecystokinin, glucagon, glucagon-like peptide-1(1-37), glucagon-like peptide-1(7-37), glucagon-like peptide-2, neurotensin, and peptide YY] and neurocrine (vasoactive intestinal peptide) peptides, and the synthetic glucocorticoid, dexamethasone, were without effect on secretion of the gut GLI peptides, at doses of 10(-12) to 10(-6) M. The results of the present study therefore demonstrate that secretion of the intestinal proglucagon-derived peptides is under the regulatory control of a wide variety of intestinal endocrine and neurocrine peptides, as well as nutrients (fats) and neurotransmitters (acetylcholine).

Animal Nutritional Physiological Phenomena

Interaction of vasoactive intestinal peptide with isolated intestinal epithelial cells from rat. 2. Characterization and structural requirements of the stimulatory effect of vasoactive intestinal peptide on production of adenosine 3':5'-monophosphate.

Porcine vasoactive intestinal peptide stimulated adenosine 3':5'-monophosphate (cyclic AMP) production in rat intestinal epithelial cells. The stimulation was dependent on time and temperature and was potentiated by the phosphodiesterase inhibitor 3-isobutyl-1-methylxanthine. Under optimal conditions (at 15 degrees C, with 0.2 mM 3-isobutyl-1-methylaxanthine, at a cell concentration up to 18 microgram DNA/ml), the cyclic AMP production produced by vasoactive intestinal peptide was constant for 10 min and stopped after 15 min incubation, at either low (1 nM) or high (30 nM) concentration of the peptide. This plateau effect was demonstrated not to be due to an inactivation of vasoactive intestinal peptide in the medium nor to an alteration of receptors for the peptide. Cyclic AMP production was sensitive to a concentration as low as 0.1 nM vasoactive intestinal peptide. Maximal stimulation of cyclic AMP levels by vasoactive intestinal peptide was observed with 30 nM vasoactive intestinal peptide and represented an 11-fold increased above basal. The dorse-response curve was monophasic with a Km of 2.3 x 10(-9) M. No cooperative effects were detected by Hill analysis. The positive non-linear relationship observed between stimulation of cyclic AMP production and occupancy of binding site was not time-dependent as indicated by experiments performed after 15, 45 and 120 min incubation. Maximal and half-maximal responses were obtained at about 70% and 7% occupation of binding sites, respectively. Chicken vasoactive intestinal peptide and porcine secretin were agonists of porcine vasoactive intestinal peptide with a 6-times and a 120-times lower potency, respectively. Among secretin analogs that were found to have low affinity for vasoactive intestinal peptide binding sites, [4-alanine, 5-valine]secretin, that resembles vasoactive intestinal peptide at the first seven amino acids at the N-terminal end, was a partial agonist of vasoactive peptide at the first seven amino acids at the N-terminal end, was a partial agonist of vasoactive intestinal peptide and others failed to stimulate cyclic AMP production. Glucagon (10microM), gastric inhibitory peptide (0.1 microM), substance, P, neurotensin, octapeptide of cholecystokinin, bovine pancreatic polypeptide, human gastrin I with leucine at residue 15, Leu-enkephalinand somatostatin (1 microM) did not alter cyclicAMP levels. Non-peptide mediators such as dopamine, serotonin, acetylcholine and histamine, tested at 10 microM, were also ineffective. Prostaglandins E2, E1 and isoproterenol, tested at 10 microM, induced an increase of cyclic AMP levels above basal but were 9.5, 13.7 and 17.5 times less efficient than vasoactive intestinal peptide, respectively. Thus vasoactive intestinal peptide is a unique stimulus of cyclic AMP production in rat intestinal epithelial cells.

1-Methyl-3-isobutylxanthine

A monoclonal antibody specific for a cytochrome c T cell stimulatory peptide inhibits T cell responses and affects the way the peptide associates with antigen-presenting cells.

A monoclonal antibody (mAb) specific for the 93-104 segment of pigeon cytochrome c (cyt) was shown to block interleukin 2 production and proliferation by pigeon cyt-specific T cells in response to the pigeon cyt 81-104 peptide using either the LK35.2 B cell hybridoma or normal splenocytes as antigen-presenting cells (APC). The mAb inhibited the response to soluble peptide antigen presented by metabolically inactive paraformaldehyde-fixed APC but not the response to APC that were pre-pulsed with Ag. These results suggest that the mAb blocked the formation of peptide-major histocompatibility complex (MHC) class II molecule complexes at the cell surface but did not displace the peptide once bound to the MHC class II molecule. As determined by direct binding experiments using labeled peptide, the major means of free peptide association with live APC was fluid-phase endocytosis. No free peptide associated directly with the MHC class II molecule at the cell surface near 0 degrees C since APC pulsed with peptide on ice did not activate cyt-specific T cells. The mAb enhanced the association of the radiolabeled peptide with APC at 4 degrees C apparently by binding of the peptide-mAb complex to Fc receptors. By stripping molecules from the LK35.2 cell surface using a nonspecific protease it was shown that the peptide-mAb complexes were not internalized either at 4 degrees C or 37 degrees C. Since the mAb was found to stably bind the peptide at pH levels below that of endosomes (pH 5.5-6.2) even if the peptide-mAb complexes were taken up by fluid-phase endocytosis, it is likely that the peptide would not be able to associate with MHC class II molecules inside the APC. This mAb appears to inhibit T cell activation by blocking the formation of peptide-MHC class II molecule complexes at the cell surface and by interfering with uptake of the peptide into endosomes. Therefore, it is different from other antibodies that have been reported to block T cell receptor recognition of preformed peptide/MHC class II molecule complexes.

Animals

Clearance of brain natriuretic peptide in patients with chronic heart failure: indirect evidence for a neutral endopeptidase mechanism but against an atrial natriuretic peptide clearance receptor mechanism.

1. Brain natriuretic peptide is a new natriuretic hormone with striking similarity to atrial natriuretic peptide, but there are no previous data concerning its clearance in man. Two pathways of clearance for atrial natriuretic peptide are recognized: degradation by neutral endopeptidase and binding to atrial natriuretic peptide clearance receptors. We have examined the effect of candoxatril, an inhibitor of neutral endopeptidase (dose range 10-200 mg), and the effect of an infusion of a pharmacological dose [45 micrograms (90 micrograms in two patients)] of synthetic human atrial natriuretic peptide on plasma human brain natriuretic peptide-like immunoreactivity levels in seven patients with mild to moderate chronic heart failure. 2. Plasma human brain natriuretic peptide-like immunoreactivity levels were elevated in all patients (mean +/- SEM 22.0 +/- 6.2 pmol/l) compared with healthy control subjects (1.3 +/- 0.2 pmol/l, n = 11). 3. In all patients, candoxatril increased both plasma atrial natriuretic peptide (P less than 0.05) and plasma human brain natriuretic peptide-like immunoreactivity (P less than 0.05) levels. 4. By contrast, an exogenous infusion of atrial natriuretic peptide had no effect on plasma human brain natriuretic peptide-like immunoreactivity levels despite increasing the plasma atrial natriuretic peptide concentration to 424 +/- 74 pmol/l, which is a level of atrial natriuretic peptide which would have 'swamped' all atrial natriuretic peptide clearance receptors. 5. We have therefore shown that plasma human brain natriuretic peptide-like immunoreactivity levels in chronic heart failure are increased by a neutral endopeptidase inhibitor, but are unchanged by an exogenous infusion of atrial natriuretic peptide.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged

Application and limitations of the multiple antigen peptide (MAP) system in the production and evaluation of anti-peptide and anti-protein antibodies.

The multiple antigen peptide (MAP) system has been proposed as a novel and valuable approach for eliciting antibodies to peptides and developing synthetic vaccines. The MAP system consists of a small immunogenically inert core matrix of lysine residues with alpha- and epsilon-amino groups for anchoring multiple copies of the same or different synthetic peptides. Several MAP systems, each containing eight copies of 6-15 residue-long peptides derived from the terminal and central regions of various proteins were analyzed in this study. The immunogenicity of MAPs was compared to that of the same peptides linked to carrier protein by means of conventional conjugation procedures. The various peptide antisera were tested in ELISA with homologous peptides conjugated to a carrier protein via their C terminal (as in the MAP system) or their N terminal end, or with their parent proteins. The antigenic properties of MAPs were studied with anti-peptide sera obtained by classical methods and with anti-protein sera. The results showed that the MAP system was an efficient antigen in ELISA except when the peptide corresponded to a C terminal epitope. However, the value of MAPs for raising anti-peptide antibodies cross-reactive with the cognate protein appeared much more limited. In the case of one N terminal peptide, the MAP construction was not immunogenic while the conventionally conjugated peptide induced antibodies that reacted strongly with the corresponding protein. In the case of the two C terminal peptides tested, the antibodies raised against MAP constructs reacted well with homologous MAPs but did not cross-react with the whole protein. Only in the case of a peptide from an internal domain of histone H2A did immunization with a MAP generate antibodies that cross-reacted with the protein.

Amino Acid Sequence

Suprasensitivity to calcitonin gene-related peptide but not vasoactive intestinal peptide in women with chronic pelvic pain.

Chronic pelvic pain in women is associated with radiological evidence of pelvic venous dilatation and reduced flow, termed 'pelvic congestion'. The aim of this study was to elucidate a possible role in this condition for vasoactive intestinal peptide and calcitonin gene-related peptide, both localized in perivascular nerves in the ovaries and uterus. Healthy volunteers and women with chronic pelvic pain and venous congestion received intravenous infusions of vasoactive intestinal peptide (n = 15), calcitonin gene-related peptide (n = 15) or a bland infusate (n = 7). Changes in the uterovaginal and skin blood flow were assessed by continuous measurement of vaginal, axillary, cheek and hand temperature. During calcitonin gene-related peptide infusion median hand temperature changes were +0.97 degrees C in women with pelvic pain and -0.03 degrees C in healthy volunteers (p < 0.05). There were no differences between groups in hand and cheek temperature responses to vasoactive intestinal peptide infusion. Vasoactive intestinal peptide and calcitonin gene-related peptide appeared to dilate the uterovaginal vasculature in healthy subjects but not in those with pelvic pain. Vasoactive intestinal peptide and calcitonin gene-related peptide did not provoke pain in healthy subjects but in those with pelvic pain, symptoms were significantly exacerbated during calcitonin gene-related peptide infusion but not by vasoactive intestinal peptide. Changes in plasma follicle stimulating hormone, luteinizing hormone and oestradiol during either infusion were not significant. These findings indicate greater sensitivity to calcitonin gene-related peptide in women with pelvic pain and suggest a possible underlying neurovascular disorder.

Adult

Evidence that some preganglionic sympathetic neurons in the rat contain vasoactive intestinal peptide- or peptide histidine isoleucine amide-like immunoreactivities.

Physiological studies have established that preganglionic sympathetic nerve fibers innervating the rat superior cervical ganglion release a second transmitter, in addition to acetylcholine. Based on pharmacological and histochemical investigations, possible candidates for this non-cholinergic neurotransmitter include vasoactive intestinal peptide and peptide histidine isoleucine amide. For example, previous immunohistochemical studies have demonstrated that antisera raised against both of these peptides stain neural processes in the rat preganglionic cervical sympathetic trunk and in the superior cervical ganglion. In the present study, it was found that, when the cervical sympathetic trunk was ligated, vasoactive intestinal peptide- and peptide histidine isoleucine amide-like immunoreactivities built up on both sides of the ligature. In addition, examination of the thoracic spinal cord in colchicine-treated animals revealed vasoactive intestinal peptide- and peptide histidine isoleucine amide-like immunoreactivies in neuronal cell bodies in the intermediolateral cell column and in the region of the lateral funiculus adjacent to it. In a second group of animals in which retrograde tracing techniques were used, these two regions of the spinal cord were shown to contain most of the cell bodies of the preganglionic neurons that project to the superior cervical ganglion. Smaller numbers of retrogradely labeled neurons were found dorsal to the central canal and in the nucleus intercalatus. When either vasoactive intestinal peptide- or peptide histidine isoleucine amide-like immunostaining and retrograde labeling were examined in the same animals, double-labeled neurons were found in the intermediolateral cell column and in the lateral funiculus. These data demonstrate that vasoactive intestinal peptide- and peptide histidine amide-like immunoreactivities are present in certain of the preganglionic neurons that project to the superior cervical ganglion, supporting the hypothesis that vasoactive intestinal peptide and peptide histidine isoleucine amide are released in the ganglion when these preganglionic neurons are activated.

Animals

Plasma concentrations and comparisons of brain natriuretic peptide and atrial natriuretic peptide in normal subjects, cardiac transplant recipients and patients with dialysis-independent or dialysis-dependent chronic renal failure.

1. We have developed a radioimmunoassay for the measurement of immunoreactive brain natriuretic peptide (1-32) in human plasma. Simultaneous measurements of atrial natriuretic peptide have also been carried out to allow for direct comparison between circulating brain natriuretic peptide and atrial natriuretic peptide. Plasma levels of immunoreactive brain natriuretic peptide (means +/- SEM) were 1.1 +/- 0.1 pmol/l in 36 normal healthy subjects and were significantly elevated in cardiac transplant recipients (18.8 +/- 3.9 pmol/l, n = 12) and in patients with dialysis-independent (8.8 +/- 1.5 pmol/l, n = 11) or dialysis-dependent (41.6 +/- 8.8 pmol/l, n = 14) chronic renal failure. Similarly, in these groups of patients plasma levels of atrial natriuretic peptide were also significantly raised when compared with those in the group of normal healthy subjects. 2. The plasma level of atrial natriuretic peptide was significantly higher than that of brain natriuretic peptide in normal subjects and in patients with dialysis-independent chronic renal failure, with ratios (atrial natriuretic peptide/brain natriuretic peptide) of 2.8 +/- 0.2 and 2.2 +/- 0.3, respectively. However, in both cardiac transplant recipients and patients on dialysis plasma levels of atrial natriuretic peptide and brain natriuretic peptide were similar, with ratios of 1.3 +/- 0.2 and 1.0 +/- 0.1, respectively, in these two groups. 3. Plasma levels of brain natriuretic peptide and atrial natriuretic peptide were significantly correlated in the healthy subjects and within each group of patients. When all groups were taken together, there was an overall correlation of 0.90 (P < 0.001, n = 73).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult