• DOI:10.1111/j.1476-5381.1996.tb15271.x
• Corpus ID: 12919854

Effects of levodropropizine on vagal afferent C‐fibres in the cat

@article{Shams1996EffectsOL,
  title={Effects of levodropropizine on vagal afferent C‐fibres in the cat},
  author={Hashim Shams and Luisa Daffonchio and Peter Scheid},
  journal={British Journal of Pharmacology},
  year={1996},
  volume={117}
}

• H. Shams, L. Daffonchio, P. Scheid
• Published 1 March 1996
• Biology, Chemistry, Medicine
• British Journal of Pharmacology

1 Levodropropizine (LVDP) is an effective antitussive drug. Its effects on single‐unit discharge of vagal afferent C‐fibres were tested in anaesthetized cats to assess whether an inhibition of vagal C‐fibres is involved in its antitussive properties. Vagal C‐fibres, identified by their response to phenylbiguanide (PBG), were recorded via suction electrodes from the distal part of the cut vagus. Based on their response to lung inflation, C‐fibres were classified as pulmonary (19 fibres) or non‐pulmonary (6 fibres). 2 PBG increased the discharge rate of both C‐fibre types and activated a respiratory reflex causing apnoea. This reflex was abolished when the second vagus nerve was cut as well, while PBG‐mediated stimulation of the C‐fibres was not affected by vagotomy. 3 LVDP was administered intravenously and the C‐fibre response to PBG was compared with that before administration of the drug. LVDP reduced both the duration of apnoea and the response of the C‐fibre to PBG. 4 Comparison of the C‐fibre responses to PBG and to a mixture of PBG and LVDP revealed that the period of apnoea was shortened and the discharge rate of the C‐fibre reduced when LVDP was present. 5 The LVDP‐induced inhibition of the C‐fibre response to PBG was on average 50% in pulmonary and 25% in non‐pulmonary fibres. 6 These results suggest that LVDP significantly reduces the response of vagal C‐fibres to chemical stimuli. It is, thus, likely that the antitussive effect of LVDP is mediated through its inhibitory action on C‐fibres.