Jørgen C. Jørgensen

Structure-function studies on neuropeptide Y and pancreatic polypeptide — evidence for two PP-fold receptors in vas deferens

The biological effects of neuropeptide Y (NPY), rat pancreatic polypeptide (rPP), hybrid analogs of NPY and PP, and C-terminal fragments of NPY were studied in the field-stimulated rat vas deferens model. The results were correlated with peptide binding experiments in Y1 and PP receptor assays on rat PC-12 cells and Y2 receptors on porcine hippocampal membranes. NPY and rPP inhibited the electrically induced contractions in the vas deferens with an IC50 of 25 and 22 nM respectively. However, in contrast to NPY, rPP could not totally block muscle activity. The inhibitory action of the long C-terminal fragment of NPY, NPY-(19-36) and NPY-(11-36), indicated that NPY acts through a Y2 receptor in the vas deferens. The structural basis for the differential recognition of NPY and PP by Y2 receptors and partly also by PP receptors, could be defined with hybrid analogs of PP and NPY. The analogs, [Ile31,Gln34]PP and [Leu31,Pro33]NPY reacted in the vas deferens preparation in accordance with their relative potency in the Y2 and PP receptor assays. [Ile31,Gln34]PP, which bound to the Y2 receptor like NPY, was also able to block the part of the contractile response which was resistant to rPP. It is concluded that in the vas deferens, PP-fold peptides act through two types of receptors: Y2 and PP, and that residues in the C-terminal part of the molecules determine the differential recognition of the peptides by these receptor types.

Stem villous arteries from the placentas of heavy smokers: Functional and mechanical properties☆☆☆

OBJECTIVE The aim of the study was to compare the mechanical and functional properties of isolated small stem villous arteries from the placentas of women who smoked heavily (>/=15 cigarettes/d) during pregnancy with those from the placentas of nonsmokers. STUDY DESIGN Isolated stem villous arteries were mounted in small-vessel myographs. Circumference-tension relationships were established with 124 mmol/L potassium chloride. Concentration-response curves were obtained for endothelin 1, prostaglandin F2alpha, vasoactive intestinal peptide, corticotropin-releasing hormone, sodium nitroprusside, and cadmium chloride. The effect of nitric oxide was examined with N omega-nitro-l -arginine. RESULTS Stem villous arteries from the heavy smoking group developed a significantly lower tension than did those from nonsmokers at 6 of 9 steps of the circumference-tension experiment (P <.05). Endothelin 1 evoked a significantly greater maximum vasoconstrictive response in stem villous arteries from heavy smokers than in those from nonsmokers (P <.05). CONCLUSION Stem villous arteries of heavy smokers have altered mechanical properties and a greater vasoconstrictive response to endothelin 1 than do those from nonsmokers. These changes may compromise fetal placental blood flow and thereby contribute to the lower birth weights seen among infants born to heavy smokers.

Neuropeptide Y (NPY) in Human Penile Corpus Cavernosum Tissue and Circumflex Veins—Occurrence and in Vitro Effects

The concentration and distribution of neuropeptide Y (NPY) within the penile corpus cavernosum (CC) and in penile circumflex veins (CV) from healthy potent males was investigated by immunochemistry and immunohistochemistry. The concentrations were assessed to 28.6 pmol/gm. (CC) and 15.8 pmol/gm. (CV) respectively. Gel filtration on CC tissue extracts demonstrated a single peak of NPY-immunoreactivity (NPY-IR) similar to synthetic human NPY. The NPY-IR was confined to nerve fibers seemingly innervating smooth muscle cells. In vitro myographic examinations demonstrated contractile activation by NPY in 2/8 CC strips and in 5/8 CV strips. The mean contractile force was 1.17 +/- 0.62 mN (18.3 +/- 15.8% of the K(+)-induced contraction) and 2.42 +/- 0.42 mN (31 +/- 12%) respectively. NPY 10(-7) and 10(-6) M displayed a potentiating effect on the response to NA 10(-9) in one of six CC and four of six CV preparations. It is suggested that NPY could add to the contractile effect of NA in detumescence and in maintenance of the resting state; contribution of NPY to the veno-occlusive mechanism at initiation of erection is another putative physiological function.

Vascular effects and cyclic AMP production produced by VIP, PHM, PHV, PACAP-27, PACAP-38, and NPY on rabbit ovarian artery.

The relationship between vessel tone and cAMP production induced by vasoactive intestinal polypeptide (VIP), peptide histidine methionine (PHM), peptide histidine valine (PHV), pituitary adenylate cyclase activating polypeptide (PACAP-27 and PACAP-38), and neuropeptide Y (NPY) was investigated in rabbit ovarian arteries in vitro. VIP, PHM, PHV, PACAP-27, and PACAP-38 added in single-dose experiments (10(-9), 10(-8), 10(-7), and 10(-6) M) induced all a significant dose-related relaxation of noradrenaline (NA)-precontracted vessels and displayed similar potencies. VIP, PHM, PHV, PACAP-27, and PACAP-38 all increased cyclic adenosine monophosphate (cAMP) accumulation. The cAMP accumulation induced by PACAP-27 and PACAP-38 was five times higher than the cAMP content induced by the other three peptides. The peptide-induced smooth muscle relaxation did not correlate to the cAMP accumulation. NPY (10(-7) M) markedly reversed the relaxations induced by VIP, PHM, PHV, PACAP-27, and PACAP-38, but did not influence the cAMP production induced by these peptides. In conclusion, the relaxation induced by VIP, PHM, PHV, PACAP-27, and PACAP-38 and the contraction induced by NPY are not solely related to the changes of cAMP contents. These findings indicate that in addition to cAMP, another intracellular signal transduction pathway may be involved in the relaxation and contraction induced by these peptides in rabbit ovarian artery.

Interaction between norepinephrine, NPY and VIP in the ovarian artery.

The in vitro effect and the interaction between norepinephrine (NE), neuropeptide Y (NPY) and vasoactive intestinal peptide (VIP) were studied in dissected segments of the rabbit ovarian artery. In addition, the structural requirement of the NPY receptor was investigated using NPY peptide analogs. NE induced a dose-dependent vasoconstriction with an Emax of 131.4 +/- 2.9% of K(+)-induced constriction. The vasoconstrictor effect of NPY was less than 5% of K(+)-induced vasoconstriction. Incubation of the artery with 10(-7) M NPY for 4 min induced a significant potentiation of NE-induced contractions. The selective NPY Y1 receptor agonist [Leu31, Pro34]NPY was also able to potentiate the NE response at the half-maximum contraction level, but not NPY(11-36), an NPY peptide fragment predominantly stimulating the NPY Y2 receptor. NPY exerted a dose-dependent vasoconstrictor effect on vessels contracted for 20 min with 10(-6) M NE. VIP induced a dose-dependent relaxation of vessels contracted with 10(-6) M NE. The VIP-induced relaxation could be reversed by NPY. In conclusion, receptors capable of interacting with NPY, presumably of the Y1 type, and VIP are present in the rabbit ovarian artery, and activation of these receptors may profoundly influence the response of the artery to norepinephrine.

The influence of neuropeptide Y and norepinephrine on ovulation in the rat ovary

Neuropeptide Y (NPY) was measured in tissue extracts from ovaries of rats treated with pregnant mare serum gonadotropin (PMSG). The extracted NPY-immunoreactive material was identical to synthetic human NPY with regard to size and hydrophobicity as evaluated by gel filtration and high performance liquid chromatography. The concentration of NPY was related to the estrous cycle and a maximum was observed in relation to the endogenous luteinizing hormone (LH) peak. NPY immunoreactivity was demonstrated by immunohistochemistry to be localized within nerve fibers supplying blood vessels and follicles. The increase in the NPY content could not be related to accumulation around specific ovarian structures. Employing an in vitro set-up, NPY (10(-7) M) was unable to induce ovulation and did not increase the ovulation rate in LH-stimulated ovaries. The combination of NPY (10(-7) M) and NE (10(-7) M) did not significantly increase the number of ovulations compared to that induced by NE (10(-7) M) alone. In conclusion, NPY content in the ovary is related to the estrous cycle, but NPY does not seem to have any direct effect on the ovulatory process.

Neuropeptide Y reduces ovarian blood flow in the rabbit

Neuropeptide Y-containing nerve fibers have previously been demonstrated to innervate the mammalian ovary. These nerve fibers innervate primarily the vasculature. In this study we have developed a method for in vivo measurement of the ovary blood flow rate by means of the 133Xe method. Using this technique we measured the ovary blood flow rate and investigated the dose-response relationship between close intraarterial-injected NPY and the ovary blood flow rate. A monoexponential washout curve for 133Xe was found for the whole washout process, ensuring that the blood flow rate at any time could be calculated from the curve. We found a mean blood flow rate in the nonpregnant rabbit ovary at 43.6 +/- 4.4 ml.(100 g)-1.min-1 (mean +/- SEM). Injection of NPY (20, 200, 2000 pM) in the aorta close to a. ovarica resulted in a dose-dependent decrease in the ovarian blood flow rate with a maximum reduction to 40.7 +/- 6.3% (mean +/- SEM) of the control blood flow rate. These findings make it likely that receptors able to interact with NPY are present in the vasculature of the rabbit ovary.

Stimulation by the Ancestral Member of the CCK/Gastrin Family, Cionin, of Trout Gallbladder Contraction

Cholecystokinin (CCK) and gastrin constitute a peptide family sharing the amidated COOH-terminal tetrapeptide -Trp-Met-Asp-Phe . NH2 which is crucial for biological activity of both. In mammals, gallbladder contraction is induced by sulfated CCK (CCK-s), whereas gastrin has a much lower potency. As indicated by specific radioimmunoassays, CCK-like peptides are also present in lower vertebrates, but their exact structures and functions remain to be elucidated. Recently, the ancestral cionin was identified in the protochordate Ciona intestinalis. * With two sulfated Tyrs, cionin is structurally a hybrid of CCK and gastrin (FIG. 1). The coho salmon gallbladder smooth muscle receptors do not distinguish between CCK and gastrin, but require the peptide to be sulfated.2 These findings suggest that the endogenous peptide resembles cionin. The present work (1) investigates the effect of cionin on smooth muscle contraction of the rainbow trout (Oncorhyncus mykiss) gallbladder and (2) evaluates the potencies of the highly specific (in mammalian systems) receptor antagonists L-364,718 (specific for CCKA-receptors) and L-365,260 (specific for CCKBor gastrin type-receptors). Experiments were performed essentially as described by Vigna and Gorbman.2 Our results confirm and extend this previous report. Cionin, CCK-8-s, and gastrin17-s induced concentration-dependent contractions of muscle strips with equal efficacy and similar potency, EDso being 42 nM, 23 nM, and 74 nM, respectively (FIG. 2). These were significantly different from the potencies of the nonsulfated forms,

The effect of a preoperative single-dose methylprednisolone on postoperative pain after abdominal hysterectomy: a randomized controlled trial

OBJECTIVE Methylprednisolone has been shown to have analgesic effects after orthopedic surgery. The objective of this trial was to compare the effect of 125 mg methylprednisolone with placebo on postoperative pain after abdominal hysterectomy. STUDY DESIGN In this randomized double-blinded placebo-controlled trial women scheduled for elective abdominal hysterectomy (n=59) were randomized to preoperatively receive either 125 mg methylprednisolone or saline intravenously. Primary outcome was postoperative pain measured on a 0.0-10.0 visual analog scale and assessed at rest and during mobilization repeatedly the first 24h and daily on the 2nd to 7th postoperative day. Secondary outcomes were postoperative use of opioids and antiemetics, vomiting, C-reactive protein levels, and time to mobilization and discharge. Repeated measures including the primary outcome were analyzed with linear mixed models. RESULTS Forty-nine cases were analyzed (methylprednisolone n=25, placebo n=24). Pain scores were significantly higher in the methylprednisolone group compared to the placebo group during mobilization (0.79 [95% confidence intervals (CI) 0.07-1.50] P=0.03) but not at rest (0.55 [95% CI: -0.06 to 1.16] P=0.08). There was no difference between the methylprednisolone and placebo group regarding use of opioids (P=0.24) and antiemetics (P=0.14), number of vomits (P=0.26), and time to mobilization (P=0.24) and discharge (P=0.28). C-reactive protein levels were significantly higher in the placebo group (P=0.01). CONCLUSIONS This trial showed no beneficial effect of methylprednisolone on postoperative pain after abdominal hysterectomy. Methylprednisolone significantly lowered postoperative CRP levels. CLINICAL TRIAL REGISTRATION ClinicalTrial.gov: www.clinicaltrials.gov: NCT01106547.