Coexistence of somatostatin- and avian pancreatic polypeptide (APP)-like immunoreactivity in some forebrain neurons

The indirect immunofluorescence technique was used to demonstrate the coexistence of somatostatin together with avian pancreatic polypeptide-like immunoreactivity within certain neurons of the rat forebrain. Numerous neurons containing these peptides were observed in the neocortex, hippocampus, olfactory tubercle, striatum, nucleus accumbens and lateral septum. In studies of serial sections stained alternately for these two peptides, and in restaining experiments, It could be determined that in many neurons in these areas these two peptides coexisted. In other brain areas such as the anterior periventricular hypothalamus, somatostatin cells were never found to contain avian pancreatic polypeptide-like immunoreactivity. Also, within the pancreas these two peptides were never found to coexist in the same cells. The findings represent a further example of the coexistence of more than one neuropeptide within a single neuron.     

Falloposcopy in conjunction with laparoscopy: possibilities and limitations

Falloposcopy is a transvaginal microendoscopic technique to explore the human Fallopian tube from the uterotubal ostium to the fimbrial end. Falloposcopy provides a unique possibility to visualize endotubal disease and may be used therapeutically for removal of debris and for cutting down filmy intraluminal adhesions. To assess the clinical performance of falloposcopy as part of an infertility investigation, a total of 43 women scheduled for laparoscopy as part of an investigation of infertility had a falloposcopy performed in conjunction with the laparoscopy. All women were investigated at Danderyd Hospital, Stockholm and Akademiska Hospital, Uppsala, during 1995 and 1996. Images from the endosalpinx were obtained in 26 of 43 women (60.5%). In 10 women (23.3%), it was possible to obtain images from both tubes. No images were of sufficient quality to describe the entire tubal mucosa in detail. Falloposcopy represents a unique tool for visualization of endotubal disease and may provide a valuable instrument for in-vivo exploration of tubal physiology. However, certain technical problems limit the usefulness of this method in routine clinical practice. These technical problems have to be solved before falloposcopy can achieve a central position in investigation and treatment of tubal disease.      

Neuropeptide Y- and alpha-adrenergic receptors in pig spleen: localization, binding characteristics, cyclic AMP effects and functional responses in control and denervated animals

The localization of neuropeptide Y binding sites in the pig spleen, as revealed by [125I]Bolton-Hunter-labelled porcine neuropeptide Y and alpha 1-adrenergic receptor binding sites, as revealed by [125I](2-beta/4-hydroxy-phenyl/-ethylaminomethyl)-tetralone as radioligand, was compared with the distribution of neuropeptide Y and noradrenaline nerves, the latter revealed by tyrosine hydroxylase and dopamine-beta-hydroxylase, using immunohistochemistry. A large degree of codistribution was obtained between [125I]neuropeptide Y and alpha 1-binding sites in the capsule, trabeculae, blood vessels and the red pulp of the spleen. Neuropeptide Y and tyrosine hydroxylase as well as dopamine-beta-hydroxylase-positive nerves were identical in the spleen and had a similar gross distribution pattern as the [125I]neuropeptide Y and alpha 1 binding sites. In functional studies using the isolated blood-perfused spleen from pentobarbital-anaesthetized pigs, neuropeptide Y, noradrenaline and the alpha 1-selective agonist phenylephrine contracted the capsule and induced vasoconstriction in the spleen in vivo. However, the selective alpha 2-adrenoceptor agonists clonidine and azepexole had no effects on blood flow or perfusion pressure, suggesting that postjunctional alpha-receptors were of the alpha 1 type. Neuropeptide Y inhibited the forskolin-evoked, cyclic adenosine monophosphate formation in vitro. The [125I]neuropeptide Y binding, with an equilibrium-dissociation constant of 503 +/- 73 pM and a maximal number of specific binding sites of 23 +/- 3 fmol/mg protein, the neuropeptide Y-induced perfusion-pressure increase in vivo and the inhibition of forskolin-evoked cyclic adenosine monophosphate formation in vitro were dependent on the amidation of the C-terminal portion of the peptide molecule. Furthermore, the effects of neuropeptide Y were not changed by alpha- and beta-adrenoceptor blockade using prazosin and propranolol. Two weeks after postganglionic denervation the neuropeptide Y and the noradrenaline contents of the pig spleen were reduced by 97% and 99%, respectively. These changes were associated with a selective supersensitivity for the noradrenaline-induced perfusion-pressure increase in vivo compared with the effect of neuropeptide Y. However, a similar potentiation of the noradrenaline effect was induced by the monoamine-uptake blocker desipramine in the absence of denervation, and there was no change in the functional response to phenylephrine after denervation.(ABSTRACT TRUNCATED AT 400 WORDS)     

Hypermetria in forelimb target-reaching after interruption of the inhibitory pathway from forelimb afferents to C3-C4 propriospinal neurones

Forelimb target-reaching in cats with a transection at C5/6 of the cortico- and rubrospinal tracts is known to depend on C3-C4 propriospinal neurones (PNs). An additional lesion transecting the dorsal column (DC) in C5/6, caudal to the C3-C4 PNs, gave pronounced hypermetria in lifting and protraction during target-reaching. If the additional DC lesion instead was made in C2, rostral to the C3-C4 PNs, there was only small hypermetria in lifting and none in protraction. It is postulated that the hypermetria after the C5/6 DC lesion is due to interruption of the inhibitory pathway from the forelimb to the C3-C4 PNs. It is suggested that feedback control from the forelimb of the premotoneurones is an integral part of the control of normal target-reaching.     

Splanchnic and renal vasoconstriction during neuropeptide Y infusion in healthy humans.

To assess whether neuropeptide Y (NPY) causes vasoconstriction in human splanchnic and renal tissues, six healthy subjects were given NPY intravenously in the basal resting state for 15 min. The NPY dose of 10, 25, and 50 pmol kg-1 min-1 was increased every 5 min. The infusion was accompanied by elevated arterial plasma levels of NPY-like immunoreactivity (Li) which were 15, 40, and 85 times higher than the basal value. After the infusion plasma NPY-Li fell with two half-lives of 5 +/- 0.4 and 29 +/- 1.7 min but was still 4 times the basal values 60 min after the infusion (P less than 0.01). A vasoconstrictor effect was seen at about 500 pM plasma NPY-Li. During the NPY infusion splanchnic and renal blood flows decreased by 26% and 29% respectively. The blood flows in these regions were still below the basal value 40 to 60 min after the NPY infusion. Plasma noradrenaline fell by 20% (P less than 0.02) and arterial glucose by 3% (P less than 0.005) during the NPY infusion. It is concluded that NPY causes a dose-dependent long-lasting vasoconstriction in human renal and splanchnic tissues. The results also suggest that elevated plasma NPY-levels may be associated with changes in the turnover of noradrenaline and glucose.     

Differential release of calcitonin gene-related peptide and neuropeptide Y from the isolated heart by capsaicin, ischaemia, nicotine, bradykinin and ouabain

The influence of various drugs as well as total ischaemia on the outflow of calcitonin gene-related peptide (CGRP), which is present in sensory nerves, and neuropeptide Y (NPY), which is co-stored with noradrenaline (NA), from the isolated guinea-pig heart, was studied in vitro. Capsaicin exposure and total ischaemia for 5-30 min induced a Ca2+-dependent increase in the outflow, suggesting release, of CGRP- but not NPY-like immunoreactivity (LI) from the heart. When characterized by high performance liquid chromatography (HPLC), the CGRP-LI present in heart extracts and the released CGRP-LI by capsaicin eluted in a major peak corresponding to synthetic CGRP. Incubation with morphine, indomethacin or reserpine pretreatment did not influence the capsaicin-evoked release of CGRP-LI. Capsaicin pretreatment depleted the cardiac content of CGRP-LI but not NPY-LI. The increase in perfusate volume observed after 30 min ischaemia in controls was reduced after capsaicin pretreatment. Nicotine exposure induced release of CGRP- as well as NPY-LI in a concentration- and Ca2+-dependent manner. The increased outflow of NPY-LI was not influenced by capsaicin pretreatment. Among other agents tested, bradykinin and ouabain caused increased outflow of CGRP but not of NPY-LI. Noradrenaline, tyramine, histamine, vasopressin, alpha,beta methylene ATP, ATP or adenosine induced changes in cardiac contractility or flow but did not evoke any detectable release of CGRP- or NPY-LI. In conclusion, the release of multiple neuropeptides can be studied in combination with contractile recordings using the isolated perfused guinea-pig whole heart preparation. Activation of cardiac sensory nerves by capsaicin, nicotine, bradykinin and ouabain, as well as ischaemia, induced release of CGRP while nicotine also evoked NPY release.     

Reduction of latex-allergen content in Swedish medical catheter balloons – a survey of 3 years' production

Anaphylactic reactions after intravascular exposure to natural rubber latex (NRL) have been reported. Thus, there is an urgent need to produce medical devices with the lowest possible latex-allergen content. The latex-allergen concentration in extracts prepared from 92 lots of medical catheter (MC) balloons, manufactured by Nolato Polymer AB, Torekov, Sweden, from April 1993 to March 1996, was measured with an EAI (IgE antibody inhibition) assay. Inhibitory capacity was expressed in arbitrary units/ml (U/ml) in relation to reference NRL sap, given an arbitrary value of 1000 U. Extracts from randomly selected lots were measured for protein by the modified Lowry method. Water leaching, chlorination, and treatment with savinase were used experimentally to study reduction of the latex-allergen content. The latex-allergen content in extract from the regular MC balloons varied from 0.1 to 2.9 U/ml. All the methods used to reduce the allergen content were effective, and increased leaching stabilized the allergen content at a low level. The protein concentration of the extracts varied between 9 and 100 mg/1. No correlation was found between protein and allergen content. As a result of this study, the manufacturer has extended the stage of water leaching in the production process. This study shows that cooperation between immunologists and manufacturers may result in product development and improvement.     

The inhibitory feedback pathway from the forelimb to C3-C4 propriospinal neurones investigated with natural stimulation

Light mechanical stimulation of the skin and passive joint movements in the forelimb gave effective activation of interneurones located medially in the C3-C4 segments. Such interneurones may be inhibitory to C3-C4 propriospinal neurones (PNs) and recording from PNs revealed that the stimuli which activated the interneurones evoked inhibition in the PNs. It is postulated that a movement commanded via the C3-C4 PNs evoke impulses in forelimb afferents which by negative feedback control transmission in the C3-C4 PNs and thus govern the execution of the movements.