[Respiratory responses to microinjections of leptin into the solitary tract nucleus].
Regulatory polypeptide leptin, apart from its well-known hypothalamic effects, stimulates ventilation. The present study on anaesthetised rats was undertaken to elucidate the respiratory effects of 10(-10)-10(-4) M leptin microinjected into the solitary tract nucleus, containing a high concentration of leptin receptors. Injections of 10(-8)-10(-4) M leptin induced dose-dependent increase in ventilation, tidal volume and electric activity of inspiratory muscles; 10(-6) M leptin additionally induced a short-term increase in respiratory frequency and a shortening of both inspiratory and expiratory duration. The respiratory responses to leptin is also characterised by appearance of sighs: deep and prolonged inspirations associated with an augmented burst in the activity of the inspiratory muscles and prolonged post-sigh inter-burst interval. The results taken together with evidence of high concentration of specific leptin ObRb-receptor in the solitary tract nucleus suggest involvement of endogenous leptin in the control of breathing via dorsal structures of the respiratory center.
Iniushkin
A N
AN
Iniushkina
E M
EM
Merkulova
N A
NA
D000818:Animals; D004305:Dose-Response Relationship, Drug; D005260:Female; D001239:Inhalation / Q000187:drug effects*; D020738:Leptin; D008297:Male; D009119:Muscle Contraction / Q000187:drug effects*; D018482:Muscle, Skeletal / Q000378:metabolism*; D051381:Rats; D054411:Receptors, Leptin / Q000378:metabolism*; D015657:Respiratory Transport / Q000187:drug effects* / Q000502:physiology; D017552:Solitary Nucleus / Q000378:metabolism*
D020738:Leptin; D054411:Receptors, Leptin