TY - JOUR
T1 - Cardiovascular actions of lungfish bradykinin in the unanaesthetised African lungfish, Protopterus annectens
AU - Balment, Richard J.
AU - Masini, Maria A.
AU - Vallarino, Mauro
AU - Conlon, J. Michael
N1 - Funding Information:
This work was supported by a grant from the National Science Foundation (IBN-9806997).
PY - 2002
Y1 - 2002
N2 - Bradykinin (BK) isolated from plasma of the African lungfish, Protopterus annectens, contains four amino acid substitutions compared with BK from mammals (Arg1 → Tyr, Pro2 → Gly, Pro7 → Ala, Phe8 → Pro). Bolus intra-arterial injections of synthetic lungfish BK (1-1000 pmol/kg body wt.) into unanaesthetised, juvenile lungfish (n = 5) produced a dose-dependent increase in arterial blood pressure and pulse pressure. The maximum pressor response occurred 2-3 min after injection and persisted for up to 15 min. The threshold dose producing a significant (P < 0.01) rise in pressure was 50 pmol/kg and the maximum increase, following injection of 300 pmol/kg, was 9.3 ± 2.3 mmHg. Injection of the higher doses of lungfish BK produced a significant (P < 0.05) increase in heart rate (2.8 ± 0.8 beats/min at 100 pmol/kg). In contrast, bolus intra-arterial injections of mammalian BK, in doses up to 1000 pmol/kg, produced no significant cardiovascular effects in the lungfish. The data support the existence of a functioning kallikrein-kinin system in the lungfish and demonstrate that the ligand-binding properties of the receptor(s) mediating the cardiovascular actions of lungfish BK are appreciably different from mammalian B1 and B2 receptors.
AB - Bradykinin (BK) isolated from plasma of the African lungfish, Protopterus annectens, contains four amino acid substitutions compared with BK from mammals (Arg1 → Tyr, Pro2 → Gly, Pro7 → Ala, Phe8 → Pro). Bolus intra-arterial injections of synthetic lungfish BK (1-1000 pmol/kg body wt.) into unanaesthetised, juvenile lungfish (n = 5) produced a dose-dependent increase in arterial blood pressure and pulse pressure. The maximum pressor response occurred 2-3 min after injection and persisted for up to 15 min. The threshold dose producing a significant (P < 0.01) rise in pressure was 50 pmol/kg and the maximum increase, following injection of 300 pmol/kg, was 9.3 ± 2.3 mmHg. Injection of the higher doses of lungfish BK produced a significant (P < 0.05) increase in heart rate (2.8 ± 0.8 beats/min at 100 pmol/kg). In contrast, bolus intra-arterial injections of mammalian BK, in doses up to 1000 pmol/kg, produced no significant cardiovascular effects in the lungfish. The data support the existence of a functioning kallikrein-kinin system in the lungfish and demonstrate that the ligand-binding properties of the receptor(s) mediating the cardiovascular actions of lungfish BK are appreciably different from mammalian B1 and B2 receptors.
KW - African lungfish
KW - Arterial blood pressure
KW - Bradykinin
KW - Cardiovascular
KW - Dipnoi
KW - Heart rate
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U2 - 10.1016/S1095-6433(01)00486-X
DO - 10.1016/S1095-6433(01)00486-X
M3 - Article
C2 - 11818234
AN - SCOPUS:0036159350
SN - 1095-6433
VL - 131
SP - 467
EP - 474
JO - Comparative Biochemistry and Physiology - A Molecular and Integrative Physiology
JF - Comparative Biochemistry and Physiology - A Molecular and Integrative Physiology
IS - 2
ER -