Occurrence of VIP and peptide HM in human pancreas and their influence on pancreatic endocrine secretion in man.

By immunohistochemistry it was found that VIP- and peptide HI/peptide HM (PHI/PHM)-like immunoreactivity occurred in autonomic neurons in the human pancreas. Antisera against both VIP and PHI/PHM reacted with neuronal cells in local ganglia and these ganglia also contained PHI/PHM- and VIP-immunoreactive fibre plexuses. VIP- and PHI/PHM-positive fibres were also seen close to the Langerhans' islets.

Preferential release of oxytocin in response to vasoactive intestinal polypeptide in rats.

Vasoactive intestinal polypeptide (VIP) was infused into the aorta of pentobarbitone-anesthetized rats (n = 12) in stepwise increasing doses of 0.001 to 10 micrograms/rat at rates varying from 0.3 pmol/min/kg to 3000 pmol/min/kg over 3 min.

Effect of vasoactive intestinal polypeptide (VIP) on steroidogenesis in women.

The VIPergic nervous system appears to be the major peptide-containing neuronal component in the female genital tract. Evidence has been put forward that exogenous VIP is able to stimulate progesterone secretion. In the present study the effect of human VIP (900 pmol/kg body weight per h i.

Release of vasoactive intestinal polypeptide (VIP) in breast-feeding women.

Blood samples were collected in peripheral venous blood of ten postpartum women before, during and after breast-feeding. Vasoactive intestinal polypeptide (VIP) and prolactin (PRL) were measured radioimmunochemically. A parallel significant increase in the VIP and PRL concentrations was observed following breast-feeding.

Peptides PHI and VIP: comparison between vascular and nonvascular smooth muscle effect in rabbit uterus.

The distribution and effects of the two neuropeptides, vasoactive intestinal polypeptide (VIP) and peptide histidine isoleucine amide (PHI), on vascular and nonvascular smooth muscle in the urogenital tract of nonpregnant rabbit female, were investigated. Immunoreactive VIP and PHI were present in all regions except the ovary with the highest concentration in the uterine cervix. By using in vitro tension recordings of myometrial specimens, it was demonstrated that both peptides displayed a dose-dependent inhibition of the mechanical activity.

VIP binding sites on synaptosomes from rat cerebral cortex: structure-binding relationship.

The structural requirements for VIP interaction with receptors on synaptosomes from rat cerebral cortex was investigated by the ability of VIP and VIP fragments, secretin analogues and fragments, peptides of the VIP/secretin family and several other regulatory peptides to inhibit specific 125I-VIP binding. Only large VIP fragments interacted with the VIP receptors with potencies relative to VIP ranging from 0.9-0.

Neurotransmitter-role of VIP in non-adrenergic relaxation of feline myometrium.

The feline myometrium is heavily innervated by VIP-containing nerve fibres. Transmural electrical stimulation (10 Hz, 2 msec, 150 mA) of muscle strips from feline myometrium in the presence of adrenoreceptor blocking agents caused a muscle relaxation. The smooth muscle relaxation was accompanied by a significant increase in immunoreactive VIP in the superfusate.

Torsion of the fallopian tube following tubal sterilization by electrocoagulation via a laparoscope.

Sterilization of the fallopian tube via a laparoscope is being performed with increasing frequency. A rare but serious late complication of this procedure is tubal torsion, which occurs especially after monopolar electrocoagulation where the mesosalpinx is extensively damaged. We present a case in which this complication occurred after bipolar electrocoagulation.

Influence of pregnancy and sex steroids on concentration, motor effect and receptor binding of VIP in the rabbit female genital tract.

The influence of sex steroid and pregnancy on the tissue concentration, uterine motor effect and receptor binding of VIP has been studied in the female genital tract of pregnant rabbits and oophorectomized rabbits during progesterone and/or oestrogen substitution. The concentration of immunoreactive VIP was high in the vagina and cervix, and lower in the uterine body of both pregnant and non-pregnant rabbits. A significant decrease in the VIP concentration (pmol/g wet weight) of the uterine body was observed toward term of pregnancy.

The regional distribution of receptors for vasoactive intestinal polypeptide (VIP) in the rat central nervous system.

The regional distribution of receptors for vasoactive intestinal polypeptide (VIP) was studied in the rat central nervous system (CNS). The specific binding was highest in cerebral cortex, limbic forebrain and cerebellum, whereas moderate to low binding was found in hypothalamus, thalamus, brainstem and pituitary. The lowest binding was observed in pons and spinal cord.

Development of binding sites for vasoactive intestinal polypeptide in mouse cerebral cortex and cultured cortical neurons.

Binding sites for vasoactive intestinal polypeptide (VIP) and the content of immunoreactive VIP were measured in the foetal and neonatal mouse brain cortex and primary cultures of foetal murine brain-cortical neurons and astrocytes. The amount of cortical VIP binding sites and the concentration of immunoreactive VIP were low before birth, but increased postnatally reaching adult level at about 3 weeks of age. In cultures, a similar rise in neuronal binding sites occurred after 10 days, whereas the VIP concentration remained lower than in adult brain cortex.

Vasoactive intestinal peptide (VIP) stimulates oxytocin and vasopressin release from the neurohypophyis.

The concentration of vasoactive intestinal peptide (VIP) was measured by RIA in pituitary extracts of female cats; it was significantly higher in the posterior than in the anterior lobe, 47.3 +/- 3.9 pmol/g wet wt vs.

Insulin receptors in rat brain cortex. Kinetic evidence for a receptor subtype in the central nervous system.

Binding kinetics of porcine 125I-insulin were studied in synaptosomal and microsomal fractions of rat brain cortex. Receptor binding was temperature- and pH-dependent with optimum at 4 degrees C and pH 8.0-8.

VIP receptors in pig liver cells: binding characteristics and role in degradation.

The physiological role of VIP in the liver is controversial. VIP receptors are present, but their function in the metabolic regulation is uncertain. The interaction of porcine VIP with isolated cells from pig liver was studied with respect to receptor-binding, degradation and glycogenolytic action.

Penile erection: possible role for vasoactive intestinal polypeptide as a neurotransmitter.

Concentrations of vasoactive intestinal polypeptide were measured in blood drawn from the cavernous spaces of corpus cavernosum of the human penis during tumescence and erection, and the effect of injecting the polypeptide into the cavernous spaces was studied. A significant release of the polypeptide was shown during tumescence and erection. Injection of exogenous vasoactive intestinal polypeptide induced erection.

Vasoactive intestinal polypeptide as a neurotransmitter in the female genital tract.

Vasoactive intestinal polypeptide (VIP) has been demonstrated in nerve fibers of the female genital tract localized in synaptic vesicles. The VIP-containing nerve fibers seem to innervate nonvascular smooth muscle, blood vessels, and epithelial cells. Evidence is accumulating that VIP fulfills a number of the classical criteria to be a neurotransmitter in the female genital tract.

Vasoactive intestinal polypeptide (VIP) increases vaginal blood flow and inhibits uterine smooth muscle activity in women.

The human vagina and uterus are heavily innervated by VIP-containing nerve fibres. In the present study, we have measured vaginal blood flow, transmucosal oxygen tension and uterine smooth muscle activity during stepwise intravenous infusion of vasoactive intestinal polypeptide (VIP) (0, 100, 300, 900 pmol kg-1 h-1) in non-pregnant women. Vaginal blood flow was measured by the heat clearance technique, transmucosal oxygen tension by an O2-electrode and uterine activity by a micro-tip pressure catheter in the uterine cavity.

Vasoactive intestinal polypeptide (VIP) as a putative neurotransmitter in penile erection.

The localization of vasoactive intestinal polypeptide (VIP) in the male genitourinary tract was investigated in the rabbit and man by means of radioimmunoassay and immunohistochemistry. In addition, the in vitro effect of VIP upon penile smooth muscle from man, the Vervet monkey, and the rabbit was investigated. Significant concentrations of VIP immunoreactivity were found in the human penis and all the organs of the rabbit genital tract apart from the testis.

Neuropeptides in the female genital tract: effect on vascular and non-vascular smooth muscle.

The presence of vasoactive intestinal polypeptide (VIP), substance P (SP), somatostatin, enkephalin, and avian pancreatic polypeptide (APP) in nerves in the female genital tract raises the question of their physiological significance as neurotransmitter substances. We have examined the effect of these peptides on non-vascular uterine smooth muscle in vivo as well as in vitro, and the effect on blood flow in the genital tract of rabbit and cat. SP caused a dose-dependent increase in mechanical and myoelectrical activity, an action which could be antagonized by VIP.

Multiplicity of receptors for vasoactive intestinal polypeptide (VIP): differential effects of apamin on binding in brain, uterus and liver.

Apamin is a neurotoxic octadecapeptide from bee venom, which has been shown to inhibit the non-adrenergic, non-cholinergic inhibitory innervation of the smooth muscle of the gut. Since vasoactive intestinal polypeptide (VIP) has been proposed as a possible inhibitory neurotransmitter, the effect of apamin on the receptor binding of 125I-VIP was studied using the following assays: (1) isolated synaptosomes from rat cerebral cortex, (2) crude plasma membranes from hog uterine smooth muscle, and (3) purified plasma membranes and isolated hepatocytes from hog liver. Apamin inhibited the receptor-bound 125I-VIP on membranes from brain or myometrium, although the binding affinity was 100-1000 times lower than for VIP.