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The effect of VIP was studied in muscle strips isolated from sheep rumen. This neuropeptide caused a concentration-dependent (10−9-5 ṁ 10−8 mol/l) reduction of acetylcholine-induced (5.5 ṁ 10−6 mol/l) isotonic contraction of the muscle strips. The inhibitory effect of VIP was not affected by incubation of the preparations with phentolamine, propranolol or tetrodotoxin; the relaxation exerted by VIP is therefore myogenic. Because nerve fibres containing VIP have recently been identified in ruminal smooth muscle, VIP probably acts on ruminal smooth muscles as an inhibitory transmitter. Zusammenfassung Relaxation der glatten Muskulatur des Pansens durch vasoaktives intestinales Polypeptid (VIP) Der Einfluß von VIP auf aus dem Pansen des Schafes isolierte Muskelstreifen wurde untersucht. Dieses Neuropeptid bewirkte eine konzentrationsabhängige (10−9-5 ṁ 10−8 mol/l) Verringerung der durch Acetylcholinin hervorgerufenen Kontraktion der Muskelstreifen. Der hemmende Effekt von VIP auf die Kontraktion der glatten Muskulatur des Pansens wurde durch Inkubation mit Phentolamin, Propranolol bzw. Tetrodotoxin nicht beeinflußt. Die durch VIP verursachte Relaxation ist deshalb myogen. Da kürzlich in der glatten Muskulatur des Pansens VIP-haltige Nervenfasern nachgewiesen wurden, dürfte VIP als inhibitorischer Transmitter auf die glatte Muskulatur des Pansens wirken. [ABSTRACT FROM AUTHOR]

Environmental protection and sustainable development have become an inevitable trend in many areas, including the energy industry. The development of energy supply networks is strongly correlated with the economics of energy sources as well as ecological and socio-political issues. However, the energy supply network is often distant from the social perspective. This paper therefore combines examination of perceptions and awareness of general public (web-based questionnaire) and top energy experts (a Delphi survey) on the energy supply network and identifies their potential integration in energy supply decision making processes. The results showed that public should be better informed as well as integrated into designing energy supply network as the prosumers gain power and the energy suppliers will no longer dominate the market. Public actors are ready to shape sustainable energy supply and also willing to pay 5.8% more for a sustainable energy supply. The majority are prepared to invest in renewable energy supply network close to their place of residence. Another result is that the public is calling for a shift in priority towards more sustainable and socially friendlier energy supply rather than focusing mainly on the economic and technical perspectives.

The effects of two metallocene ethylene-propylene-based elastomers (m-EPR1 and m-EPR2) differing in molecular mass and viscosity on mechanical, rheological and interfacial properties were compared. The m-EPR elastomers were added to iPP in 2.5, 5, 10, 15, and 20 vol.%. Torque values, elongation at break and impact strength measured of the iPP/m-EPR1 blends were higher than the iPP/m-EPR2 blends due to higher molten viscosity of m-EPR1 than m-EPR2 copolymer. Slight differences in Young moduli as well as in tensile strength at yield and at break might indicate that tensile properties of iPP/m-EPR blends were not significantly affected by difference in viscosity or molecular mass, miscibility and spherulite size. Optimization diagrams indicated the metallocene m-EPR copolymers are efficient impact modifiers for polypropylene and showed good balancing of mechanical properties in iPP/m-EPR blends.

The effects of various neurotransmitters and electrical field stimulation on muscle strips from the distal equine esophagus were studied. Acetylcholine (ACH) caused concentration dependent (1.1-55 x 10(-6) mol/l) contractions of the longitudinal and circular muscle strips from the distal esophagus as well as from the lower esophageal sphincter (LES). Atropine (10(-5) mol/l) blocked these contractions. Noradrenaline (NA) induced concentration related (1.1-55 x 10(-6) mol/l) contractions of the muscle strips from the LES. This excitatory effect of noradrenaline was antagonized by the alpha 1-receptor antagonist prazosin. Tetrodotoxin (5 x 10(-6) mol/l) did not affect the contractile response of the muscle strips to noradrenaline (55 x 10(-6) mol/l). Noradrenaline (1.1-55 x 10(-6) mol/l) had no excitatory effect on the circular and the longitudinal muscle strips from the esophagus. Furthermore, noradrenaline induced a concentration dependent (1.1-55 x 10(-6) mol/l) relaxation of the longitudinal muscle strips from the esophagus. The relaxing effect of NA was antagonized by the beta-receptor antagonist propranolol (10(-5) mol/l). Histamine (10(-7)-10(-6) mol/l) elicited a contraction in 4 out of 18 muscle preparations from the LES. The histamine induced contractions were partly antagonized by the H1-receptor antagonist clemastine (10(-4) mol/l) and fully abolished by the H2-receptor antagonist clemastine (10(-4) mol/l). Electrical field stimulation (EFS, 5 Hz, 2 ms; 500 mA; 10 Hz, 2 ms; 500 mA) produced tetrodotoxin sensitive contractions in all three types of muscle strips. Atropine (10(-5) mol/l) fully suppressed these contractions in most preparations.(ABSTRACT TRUNCATED AT 250 WORDS)

The effects of adrenaline, dopamine, serotonin, and different cholinergic agents on isolated muscle strips from the ansa proximalis coli in cattle were studied. Adrenaline (5 x 10(-5) mol/l) evoked a relaxing effect (p < 0.05) on longitudinal and circular muscle strips, mediated via beta- and alpha 1-receptors respectively. High concentration of dopamine (5 x 10(-4) mol/l) caused a non-significant inhibitory effect on longitudinal smooth muscles, which was probably mediated by beta- and not by dopamine-receptors. Serotonin (5 x 10(-5) mol/l) and cisapride (75 x 10(-6) mol/l) had no effect. Carbachol (2 or 10 x 10(-6) mol/l) and bethanechol (5 or 10 x 10(-5) mol/l) caused a dose-dependent (p < 0.05) contraction of both smooth muscle types. This excitatory effect was inhibited (p < 0.05) by metoclopramide (1 x 10(-4) mol/l), as well as the muscarinic agents RS-86 (5 x 10(-5) mol/l) and CGP-37,218 (37.5 or 75 x 10(-6) mol/l).

The effect of noradrenaline (NA) on smooth muscle strips from the reticular groove of adult cattle was studied. The mechanical activity of the muscle strips was recorded isometrically. Noradrenaline caused concentration dependent (1.1 x 10(-6)-55 x 10(-6) mol/l) contractions of both the transversal muscle strips from the floor and the longitudinal muscle strips from the lips of the reticular groove. This excitatory effect of noradrenaline was antagonized by the alpha 1-receptor antagonist prazosin (10(-8) mol/l) and by higher concentrations of the alpha 2-receptor antagonist yohimbine (10(-6) mol/l) and atropine (10(-5) mol/l). Tetrodotoxin (5 x 10(-6) mol/l) and latrotoxin did not affect the contractile response of the muscle strips to noradrenaline (55 x 10(-6) mol/l). Furthermore, strips stored for 24 hours in Tyrode's solution at 4 degrees C without oxygen supply maintained their full sensitivity to noradrenaline. Propranolol (10(-4) mol/l), a beta-receptor antagonist, led to a significant increase of the contractions induced by noradrenaline (55 x 10(-6) mol/l). These results suggest that noradrenaline increases the tone of the smooth muscle of the reticular groove via alpha-adrenergic receptors and decreases its tone via beta-adrenergic receptors. Both receptor types are located on the smooth muscle cells. The alpha 1-receptor mediated effect appears to be predominant.

The effect of Vasoactive Intestinal Peptide (VIP) on muscle strips from the reticular groove, the reticulo-omasal orifice (ROO) and the omasal canal was studied. VIP caused a concentration-dependent (10(-8)-5 x 10(-7) mol/l) reduction of the acetylcholine-induced (55 x 10(-6) mol/l) contraction of the reticular groove muscle preparations from calves and adult cattle. VIP was more effective in the muscle strips from calves than in those from adult cattle. Moreover, the circular muscle strips from the reticular groove were more sensitive to VIP than the longitudinal muscle strips. VIP also induced a concentration-related (10(-8)-5 x 10(-7) mol/l) relaxation of muscle strips from the calf ROO. Furthermore, both circular and longitudinal muscle strips from the omasal canal of the calf were relaxed by VIP (10(-7)-5 x 10(-7) mol/l). The relaxing effect of VIP on the circular muscle strips from the reticular groove of the calf was not significantly affected during incubation with 5 x 10(-6) mol/l tetrodotoxin. The relaxing effect of VIP therefore seems to be mediated by VIP receptors of smooth muscle cells. These properties of VIP in conjunction with its presence in nerve fibres located in the wall of the reticular groove and ROO are consistent with a role of VIP as inhibitory transmitter in this region of the bovine stomach.

The effect of noradrenaline and adrenaline on isolated smooth muscle from the reticular groove of calves was studied. Both catecholamines caused a concentration-dependent (1.1.10(-6) mol/l) contraction of the transversal muscle strips from the floor of the reticular groove. This excitatory effect was antagonized by prazosin (10(-7)) mol/l), and by high concentrations of yohimbine (10(-6) mol/l) and atropine (10(-5)) mol/l). Tetrodotoxin (3.10(-6) mol/l), an inhibitor of nerve conduction, did not change the contraction induced by catecholamines (55.10(-6)) mol/l). Catecholamines did not produce a contraction of the longitudinal muscle from the lips of the reticular groove. The beta-adrenergic agonist isoprenaline (55.10(-6) mol/l) even elicited a reduction of acetylcholine (55.10(-6)) mol/l) induced contraction of both the transversal and the longitudinal muscle from the reticular groove. The relaxing effect of isoprenaline was antagonized by propranolol (55.10(-6)) mol/l). According to these results the excitatory effect of catecholamines on the smooth muscle cells occurs through alpha-adrenergic receptors, whereas the relaxing effect is mediated by beta-adrenergic receptors of the muscle cell. The excitatory effect of catecholamines on the transversal muscle appears to be predominant. Atropine appears to be an unspecific blocking agent of alpha-adrenergic receptors.

The following parameters were determined: Rate of breathing (f): 31.95 +/- 6.73/min. Minute volume (V): 5.11 +/- 6.73 liter/min. Tidal volume (VT): 0.166 +/- 0.053 liter. Ratio expiratory to inspiratory time Et/It : 1.04 +/- 0.18. Physiological dead space (VD): 0.061 +/- 0.024 liter. Dead space quotient (VD)/VT): 29.92 +/- 1.53%. Dynamic lung compliance (C dyn): 0.06 +/- 0.06 liter/cm H2O. Maximum interpleural negative pressure during inspiration (max. neg. Ppl. Insp.): 12.00 +/- 4.06 cm H2O. Minimum interpleural negative respectively maximum interpleural positive pressure during expiration (min. neg. or pos. Ppl. Exp.): +0.07 +/- 6.53 cm H2O. Maximum change of interpleural pressure (delta Ppl. max): 11.97 +/- 3.18 cm H2O.