Galanin modulates cholinergic neurotransmission in the heart.

The role of galanin (Gal) in the modulation of cholinergic neurotransmission in the heart in wild-type (129 SvJ), and GALR1 knockout mice has been studied. The mice were anaesthetised and ventilated. Blood pressure (BP) and the increase in pulse interval evoked by stimulation of the vagus nerve (deltaPI) were recorded.

Galanin and neuropeptide Y reduce cholinergic transmission in the heart of the anaesthetised mouse.

(1) This study investigated the effects of galanin (GAL) on inhibition of cholinergic (vagal) activity in the mouse heart using control galanin knockout (GAL-KO) and GAL-1R receptor knockout (GAL-1R-KO) mice. (2) In pentobarbitone anaesthetised mice, supramaximal stimulation every 30 s of the vagus nerve innervating the heart, increased pulse interval (PI) by approximately 50 ms or decreased heart rate by approximately 100 beats min-1. This response was attenuated by intravenous administration of GAL (dose ranged from 0.

Cardiac function in neuropeptide Y Y4 receptor-knockout mice.

Autonomic control of cardiovascular function in neuropeptide Y (NPY) Y4 receptor-knockout mice was investigated using pancreatic polypeptide (PP), NPY and specific agonists and antagonists for other NPY receptors well characterised in cardiovascular function. Y4 receptor-knockout mice, anaesthetised with sodium pentobarbitone, displayed slower heart rate, indicated by a higher pulse interval and lower blood pressure compared to control mice. After vagus nerves were cut heart rate increased but was still significantly slower than in control mice.

Stabilization of the helical structure of Y2-selective analogues of neuropeptide Y by lactam bridges.

The importance of helical structure in an analogue of NPY selective for the Y2 receptor, Ac[Leu28,31]NPY24-36, has been investigated by introducing a lactam bridge between positions 28 and 32. The resulting analogue, Ac-cyclo28/32[Ala24,Lys28,Leu31,Glu32]NPY24-36, is a potent Y2-selective agonist. Structural analysis by NMR shows that this analogue forms a helical structure in a 40% trifluoroethanol/water mixture, whereas in water only the region around the lactam bridge (Lys28-Glu32) adopts helical-like structure, with both N- and C-termini being poorly defined.

Role of neuropeptide Y Y(2) receptors in modulation of cardiac parasympathetic neurotransmission.

The aim of the study was to clarify the role of the Y(2) receptor in regulation of vagal control of the heart, using Y(2)((-/-)) receptor-knockout mice. Adult Y(2)((+/+),(-/-)) mice (50% C57BL/6-50% 129/SvJ background) were anaesthetised and artificially ventilated. Arterial blood pressure and pulse interval was recorded and both vagus nerves were cut.