Intrathecal neurotensin is hypotensive, sympathoinhibitory and enhances the baroreflex in anaesthetized rat

B. Zogovic, Paul M. Pilowsky*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

16 Citations (Scopus)


Background and Purpose The neuromodulatory effects of the gut-neuropeptide neurotensin on sympathetic vasomotor tone, central respiratory drive and adaptive reflexes in the spinal cord, are not known. Experimental Approach Neurotensin (0.5 μM-3 mM) was administered into the intrathecal (i.t.) space at the sixth thoracic spinal cord segment in urethane-anaesthetized, paralysed, vagotomized male Sprague-Dawley rats. Pulsatile arterial pressure, splanchnic sympathetic nerve activity (sSNA), phrenic nerve activity, ECG and end-tidal CO 2 were recorded. Key Results Neurotensin caused a dose-related hypotension, sympathoinhibition and bradycardia. The maximum effects were observed at 3000 μM, where the decreases in mean arterial pressure (MAP), heart rate (HR) and sSNA reached -25 mmHg, -26 beats min -1 and -26% from baseline, respectively. The sympathetic baroreflex was enhanced. Changes in central respiratory drive were characterized by a fall in the amplitude of the phrenic nerve activity. Finally, administration of SR 142948A (5 mM), a potent, selective antagonist at neurotensin receptors, caused a potent hypotension (-35 mmHg), bradycardia (-54 beats min -1) and sympathoinhibition (-44%). A reduction in the amplitude and frequency of the phrenic nerve activity was also observed. Conclusions and Implications The data demonstrate that neurotensin plays an important role in the regulation of spinal cardiovascular function, affecting both tone and adaptive reflexes.

Original languageEnglish
Pages (from-to)378-389
Number of pages12
JournalBritish Journal of Pharmacology
Issue number1
Publication statusPublished - May 2012


  • baroreflex
  • blood pressure
  • intrathecal
  • neurotensin
  • phrenic nerve activity
  • SR 142948A
  • sympathetic nerve activity


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