Participation of galanin in baroreflex inhibition of heart rate by hypothalamic PVN in rat

Ying Ling Chen, Samuel H.H. Chan, Julie Y.H. Chan*

*Corresponding author for this work

Research output: Contribution to journalJournal Article peer-review

23 Scopus citations


We investigated the role of galanin (Gal) in the suppression of baroreceptor reflex (BRR) response by the paraventricular nucleus of the hypothalamus (PVN) in adult male Sprague-Dawley rats that were anesthetized with pentobarbital sodium. Electrical stimulation (10-s train of 1-ms rectangular pulses at 20-40 μA and 10-20 Hz) of, and microinjection of L- glutamate (1 nmol) into, the PVN significantly inhibited BRR response to transient hypertension induced by phenylephrine (5 μg/kg iv). Such a PVN- induced BRR suppression was appreciably antagonized by local administration of Gal antiserum (1:20), but not heat-inactivated Gal antiserum (1:20), to the nucleus tractus solitarius (NTS) bilaterally. Microinjection of Gal (100 pmol) into the NTS bilaterally also resulted in a Gal antiserum-reversible inhibition of the BRR response. Immunohistochemical results demonstrated that the distribution of Gal-containing neurons in the parvocellular subnucleus of the PVN overlapped substantially with the hypothalamic loci on which electrical or chemical activation elicited suppression of the BRR response that was significantly blunted by microinjection of Gal antiserum into the NTS. These results suggest that the PVN may participate in central cardiovascular regulation by suppressing the BRR response via galaninergic neurotransmission at the NTS.

Original languageEnglish
Pages (from-to)H1823-H1828
JournalAmerican Journal of Physiology - Heart and Circulatory Physiology
Issue number5 40-5
StatePublished - 11 1996


  • galanin antiserum
  • galanin-like immunoreactivity
  • nucleus tractus solitarius


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