Role of locus coeruleus noradrenergic neurons in cardiorespiratory and thermal control during hypoxia.
We investigated the specific role of LC noradrenergic (NA) neurons in the cardiorespiratory and thermal responses to hypoxia. Aiming this, LC NA neurons were selectively destroyed by microinjecting 6-OHDA bilaterally in the LC of male rats. Pulmonary ventilation (VE, plethysmograph), core body temperature (Tc, dataloggers), mean arterial pressure (MAP) and heart rate (fH) were measured during normoxia followed by 7% O(2) in air. Tyrosine hydroxylase (TH) immunoreactivity was performed to verify the chemical lesions effectiveness. Hypoxia caused increase in VE, decrease in Tc and did not affect fH in both sham-operated and 6-OHDA-lesioned groups. In addition, hypoxia decreased MAP in the sham-operated group and did not affect MAP in the 6-OHDA-lesioned group. LC lesion did not affect VE, MAP, fH and Tc. Thus, these results indicate that LC noradrenergic neurons do not play a role in cardiorespiratory control and thermoregulation under basal and hypoxic conditions.
Biancardi
Vivian
V
Department of Animal Morphology and Physiology, Sao Paulo State University - UNESP - FCAV Jaboticabal, SP, Brazil.
da Silva
Luana Tenório
LT
Bícego
Kênia C
KC
Gargaglioni
Luciane H
LH
D018663:Adrenergic Agents; D000818:Animals; D001794:Blood Pressure / Q000187:drug effects; D001831:Body Temperature / Q000187:drug effects; D001833:Body Temperature Regulation / Q000187:drug effects*; D001921:Brain / Q000187:drug effects / Q000378:metabolism; D002320:Cardiovascular Physiological Phenomena / Q000187:drug effects*; D006339:Heart Rate / Q000187:drug effects; D000860:Hypoxia / Q000139:chemically induced; D007150:Immunohistochemistry; D008125:Locus Coeruleus / Q000166:cytology / Q000187:drug effects / Q000503:physiopathology; D008297:Male; D008845:Microinjections; D009474:Neurons / Q000378:metabolism*; D009638:Norepinephrine / Q000378:metabolism*; D016627:Oxidopamine; D012123:Pulmonary Ventilation / Q000187:drug effects*; D051381:Rats; D017208:Rats, Wistar; D012119:Respiration / Q000187:drug effects; D014446:Tyrosine 3-Monooxygenase
D018663:Adrenergic Agents; D016627:Oxidopamine; D014446:Tyrosine 3-Monooxygenase; D009638:Norepinephrine