title: B1-kinin receptors modulateMesobuthus tamulusvenom-induced vasosensory reflex responses in anesthetized rats.
abstract: OBJECTIVE
  Intra-arterial injection ofMesobuthus tamulus(BT) venom produces reflex vasosensory responses modulating cardiorespiratory parameters in albino rats. The present study was conducted to understand the role of kinin receptors in modulating vasosensory reflexes evoked by BT venom.
  
  
  METHODS
  In urethane-anesthetized rats, tracheostomy was performed to keep the airway patent. The femoral artery was cannulated proximally, as well as distally, to record the blood pressure (BP) and to inject the chemicals, respectively. Electrocardiographic and respiratory excursions were recorded to compute the heart rate (HR) and respiratory rate (RR). A group of animals was pretreated with saline/kinin receptor antagonists intra-arterially (B1/B2 receptor antagonists) before the injection of venom.
  
  
  RESULTS
  After intra-arterial injection of BT venom (1 mg/kg), there was an immediate increase in RR, which reached to 40% within 30 s, followed by a decrease of 40%. Further, there was sustained increase in RR (50%) up to 60 min. The BP started to increase at 40 s, peaking at 5 min (50%), and remained above the initial level up to 60 min. The bradycardiac response started after 5 min which peaked (50% of initial) at 25 min and remained at that level up to 60 min. In B1 receptor antagonist (des-Arg) pretreated animals, venom-induced cardiovascular responses were attenuated (by 20-25% in mean arterial pressure and HR) significantly but not in B2 receptor antagonist (Hoe-140) pretreated animals. Either of the antagonists failed to alter the RR responses.
  
  
  CONCLUSIONS
  BT venom-induced vasosensory reflex responses modulating cardiovascular parameters are mediated via B1-kinin receptors in anesthetized rats.
authors.affiliation: Department of Physiology, Institute of Medical Sciences, Banaras Hindu University, Varanasi, Uttar Pradesh, India.
authors.forename: Sanjeev K
authors.initials: SK
authors.lastname: Singh
authors.affiliation: Department of Physiology, Institute of Medical Sciences, Banaras Hindu University, Varanasi, Uttar Pradesh, India.
authors.forename: Shripad B
authors.initials: SB
authors.lastname: Deshpande
mesh_terms: D000344:Afferent Pathways / Q000187:drug effects; D000818:Animals; D001794:Blood Pressure / Q000187:drug effects; D065169:Bradykinin B1 Receptor Antagonists / Q000494:pharmacology; D002320:Cardiovascular Physiological Phenomena / Q000187:drug effects*; D006339:Heart Rate / Q000187:drug effects; D007269:Injections, Intra-Arterial; D051381:Rats; D043783:Receptor, Bradykinin B1 / Q000378:metabolism*; D012018:Reflex / Q000187:drug effects; D012143:Respiratory Physiological Phenomena / Q000187:drug effects*; D056152:Respiratory Rate / Q000187:drug effects; D012604:Scorpion Venoms / Q000633:toxicity*; D012605:Scorpions; D050916:TRPV Cation Channels / Q000378:metabolism
chemical_list: D065169:Bradykinin B1 Receptor Antagonists; D043783:Receptor, Bradykinin B1; D012604:Scorpion Venoms; D050916:TRPV Cation Channels; C493922:Trpv1 protein, rat
keywords: B1-Kinin receptor; Hoe-140; des-Arg; scorpion venom; vasosensory reflexes