TY - JOUR
T1 - Pulmonary vagal afferent stimulants in the conscious rat
T2 - Opioids and phenyldiguanide
AU - Willette, R. N.
AU - Gatti, P.
AU - Gertner, S. B.
AU - Sapru, H. N.
N1 - Funding Information:
The authors would like to thank Dr. George A. Condouris for the generous contribution of morphine sulfate and Ms. Pam Koontz for her help in preparing this manuscript. This work was supported by Grant HL 24347 from the National Institute of Health awarded to Dr. H. N. Sapru.
PY - 1982/7
Y1 - 1982/7
N2 - Phenyldiguanide (PDG, 40 μg/kg), D-ala2-met5-enkephalinamide (D-AME, 250 μg/kg) and morphine sulfate (MS, 2 mg/kg) injected into the right atrium (RA) of conscious freely moving rats produced a profound bradycardia and hypotension 1-2 sec subsequent to administration. Concomitant with the cardiovascular effects apnea occurred and lasted approximately 5 sec. Atropine methyl nitrate (2 mg/kg, RA) significantly attenuated the bradycardia and hypotension produced by all three agents. Naloxone blocked only the opioid responses. Coordinated motor activity was impaired following the administration of PDG (40 μg/kg, RA). Fifty percent of the animals receiving PDG failed to remain on a rotor rod for a 2 min period. Only 8 percent of the saline treated group fell off during this period. It was concluded that the cardiovascular, respiratory, and motor effects caused by PDG, in the conscious freely moving rat, were the result of stimulation of pulmonary vagal afferents (J-receptors). The cardiovascular effects of opioids are also believed to arise from the stimulation of J-receptors. However, unlike PDG, these effects are mediated by pulmonary opiate receptors.
AB - Phenyldiguanide (PDG, 40 μg/kg), D-ala2-met5-enkephalinamide (D-AME, 250 μg/kg) and morphine sulfate (MS, 2 mg/kg) injected into the right atrium (RA) of conscious freely moving rats produced a profound bradycardia and hypotension 1-2 sec subsequent to administration. Concomitant with the cardiovascular effects apnea occurred and lasted approximately 5 sec. Atropine methyl nitrate (2 mg/kg, RA) significantly attenuated the bradycardia and hypotension produced by all three agents. Naloxone blocked only the opioid responses. Coordinated motor activity was impaired following the administration of PDG (40 μg/kg, RA). Fifty percent of the animals receiving PDG failed to remain on a rotor rod for a 2 min period. Only 8 percent of the saline treated group fell off during this period. It was concluded that the cardiovascular, respiratory, and motor effects caused by PDG, in the conscious freely moving rat, were the result of stimulation of pulmonary vagal afferents (J-receptors). The cardiovascular effects of opioids are also believed to arise from the stimulation of J-receptors. However, unlike PDG, these effects are mediated by pulmonary opiate receptors.
KW - Cardiovascular reflex
KW - Enkephalin
KW - Morphine
KW - Motor activity
KW - Pulmonary J-receptors
KW - Pulmonary opiate receptors
KW - Vagal afferents
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U2 - 10.1016/0091-3057(82)90256-8
DO - 10.1016/0091-3057(82)90256-8
M3 - Article
C2 - 7122664
AN - SCOPUS:0019966543
VL - 17
SP - 19
EP - 23
JO - Pharmacology Biochemistry and Behavior
JF - Pharmacology Biochemistry and Behavior
SN - 0091-3057
IS - 1
ER -