Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
9118823 | Neuropeptides | 2005 | 4 Pages |
Abstract
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 (ÎPI) were recorded. Resting BP and PI were not different in control and GALR1-KO mice. In control mice an intravenous, bolus injection of Gal (0.8-13 nmol/kg; n = 4-6) attenuated the ÎPI, dose dependently from 33 ± 7% to 78 ± 9.5%. In GALR1-KO mice, Gal (0.8-13 nmol/kg) did not attenuate ÎPI at any dose (n = 3-4). In control mice intravenous, bolus injection of neuropeptide Y (NPY; 0.5-10 nmol/kg, n = 5-7) attenuated the ÎPI by 13 ± 10% to 67 ± 7% with a half time to recovery of 0.5-5 ± 1 min. In control mice, following activation of the cardiac sympathetic nerve (10 Hz for 2 min; n = 3) the ÎPI was attenuated by 92 ± 2% with a half time to recovery of 7 ± 1 min. In control mice in the presence of the β-adrenoceptor antagonist propranolol (1 mg/kg), and 1 μmol/kg BIIE0426 (an NPY Y2 receptor antagonist) the ÎPI was 57 ± 3% with a half time to recovery of 2.5 ± 0.5 min. In GALR1-KO mice, in the presence of propranolol and BIIE0426 there was no inhibition of ÎPI. In mice, it is proposed that both Gal and NPY contribute to the prolonged attenuation of parasympathetic slowing of the heart following activation of the cardiac sympathetic nerve.
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Authors
Erica K. Potter, Margaret A. Smith-White,