Influence of 5-HT2A Receptor Blockade on Phrenic Nerve Discharge at Three Levels of Extracellular K+ in Arterially-Perfused Adult Rat

Conference paper
Part of the Advances in Experimental Medicine and Biology book series (AEMB, volume 669)


Recent observations from in vitro rodent preparations suggest an important role for the serotonin-2A (5-HT2A) receptor in eupneic (basal) and gasping respiratory activities, although the precise role appears to be different in different preparations. Since these in vitro preparations are typically supplied with elevated (and different) levels of K+ to increase neuronal excitability, the role of endogenous activation of 5-HT2A receptors in these respiratory behaviors under “normal” levels of extracellular K+ ([K+]o) requires clarification. The current study sought to evaluate the influence of [K+]o on the 5-HT2A receptor-mediated effects on basal respiratory activity and the phases of the hypoxic ventilatory response (HVR), including ischemia-induced gasping in an arterially-perfused adult rat preparation. Our data demonstrate that at each level of [K+]o examined, blockade of 5-HT2A receptors increases basal phrenic burst frequency, decreases basal phrenic burst amplitude, alters basal phrenic burst pattern, and eliminates the phases of the HVR. These data support an important role for 5-HT2A receptors in respiratory control, and indicate the their role is not dependent on the level of [K+]o.


Slice Preparation Endogenous Activation Burst Frequency Hypoxic Ventilatory Response Burst Pattern 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.



This work was supported by NIH grants NS045321.


  1. Pena, F. and Ramirez, J.M. (2002) Endogenous activation of serotonin-2A receptors is required for respiratory rhythm generation in vitro. J. Neurosci. 22, 11055–11064.PubMedGoogle Scholar
  2. Solomon, I.C., Rodriguez, M.N., and Chon, K.H. (2003) Blockade of brain stem gap junctions increases phrenic burst frequency and reduces phrenic burst synchronization in adult rat. J. Neurophysiol. 89, 135–149.CrossRefPubMedGoogle Scholar
  3. St. John, W.M. and Leiter, J.C. (2008) Maintenance of gasping and restoration of eupnea after hypoxia is impaired following blockade of alpha1-adrenergic receptors and serotonin 5-HT2 receptors. J. Appl. Physiol. 104, 665–673.CrossRefGoogle Scholar
  4. Toppin, V.A., Harris, M.B., Kober, A.M., Leiter, J.C., and St. John, W.M. (2007) Persistence of eupnea and gasping following blockade of both serotonin type 1 and 2 receptors in the in situ juvenile rat preparation. J. Appl. Physiol. 103, 220–227.CrossRefPubMedGoogle Scholar
  5. Tryba, A.K., Pena, F., and Ramirez, J.M. (2006) Gasping activity in vitro: A rhythm dependent on 5-HT2A receptors. J. Neurosci. 26, 2623–2634.CrossRefPubMedGoogle Scholar

Copyright information

© Springer Science+Business Media, LLC 2010

Authors and Affiliations

  1. 1.Department of Physiology and BiophysicsStony Brook UniversityNew YorkUSA

Personalised recommendations