Blood pressure during induction and termination of the dorsal immobility response

Barry E. Hurwitz, Ronald L. Smith, Merle E. Meyer

Research output: Contribution to journalArticle

1 Scopus citations

Abstract

Evidence has indicated that afferent baroreceptor input may play a role in the induction of the dorsal and tonic immobility responses, which are behaviorally similar, but involve opposite posture changes upon induction (i.e., upright versus inverted, respectively). Information is lacking on the topography of the blood pressure response during periods of dorsal immobility. The blood pressure response of the adult Wistar rat during induction and termination of dorsal immobility was compared to the blood pressure response during a condition which controlled for posture change. Each animal received two control trials, ten dorsal immobility trials and then two control trials in two successive sessions four and ten days after surgery. A precise second-by-second topographical analysis of the dorsal immobility response revealed a sharp rise in blood pressure at trial onset of 18.4 mmHg, followed by a return below pretrial levels and then subsequent recovery back to pretrial levels by the tenth-trial second. This level was maintained until the last five seconds of immobility when a rapid blood pressure elevation occurred. This terminating elevation correlated highly with the observation of large movement and probably reflected motor activity that eventually culminated in escape from immobility. The vertical posture change of the control condition, on the other hand, resulted in a gradual diminution of blood pressure, which implied that the initial blood pressure elevation during initiation of the dorsal immobility response could not be accounted for simply by posture change. In view of the similarity between the tonic and dorsal immobility blood pressure responses despite opposite postural changes, it was suggested that the blood pressure changes at induction of dorsal immobility probably did not reflect a response to afferent baroreceptor input.

Original languageEnglish (US)
Pages (from-to)671-675
Number of pages5
JournalPhysiology AND Behavior
Volume45
Issue number3
DOIs
StatePublished - Mar 1989
Externally publishedYes

Keywords

  • Baroreceptor
  • Blood pressure
  • Dorsal immobility
  • Posture
  • Tonic immobility

ASJC Scopus subject areas

  • Physiology (medical)
  • Behavioral Neuroscience

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