title: Hypothyroidism affects D2 receptor-mediated breathing without altering D2 receptor expression.
abstract: Bromocriptine depressed ventilation in air and D2 receptor expression in the nucleus tractus solitaries (NTS) in male hypothyroid hamsters. Here we postulated that in age-matched hypothyroid female hamsters, the pattern of D2 receptor modulation of breathing and D2 receptor expression would differ from those reported in hypothyroid males. In females hypothyroidism did not affect D2 receptor protein levels in the NTS, carotid bodies or striatum. Bromocriptine, but not carmoxirole (a peripheral D2 receptor agonist), increased oxygen consumption and body temperature in awake air-exposed hypothyroid female hamsters and stimulated their ventilation before and following exposure to hypoxia. Carmoxirole depressed frequency of breathing in euthyroid hamsters prior to, during and following hypoxia exposures and stimulated it in the hypothyroid hamsters following hypoxia. Although hypothyroidism did not affect expression of D2 receptors, it influenced central D2 modulation of breathing in a disparate manner relative to euthyroid hamsters.
authors.affiliation: Division of Basic Biomedical Sciences, Sanford School of Medicine of the University of South Dakota, 414 East Clark Street, Vermillion, SD 57069, United States. Electronic address: Evelyn.Schlenker@usd.edu.
authors.forename: Evelyn H
authors.initials: EH
authors.lastname: Schlenker
authors.affiliation: Department of Cellular & Integrative Physiology, University of Nebraska College of Medicine, 985850 Nebraska Medical Center, Omaha, NE 68198-5850, United States.
authors.forename: Rodrigo
authors.initials: R
authors.lastname: Del Rio
authors.affiliation: Department of Cellular & Integrative Physiology, University of Nebraska College of Medicine, 985850 Nebraska Medical Center, Omaha, NE 68198-5850, United States.
authors.forename: Harold D
authors.initials: HD
authors.lastname: Schultz
mesh_terms: D000388:Air; D000818:Animals; D001831:Body Temperature / Q000187:drug effects / Q000502:physiology; D001971:Bromocriptine / Q000494:pharmacology; D002344:Carotid Body / Q000187:drug effects / Q000378:metabolism*; D003342:Corpus Striatum / Q000187:drug effects / Q000378:metabolism*; D006224:Cricetinae; D018491:Dopamine Agonists / Q000494:pharmacology; D005260:Female; D007037:Hypothyroidism / Q000188:drug therapy / Q000378:metabolism*; D000860:Hypoxia / Q000188:drug therapy / Q000378:metabolism; D007211:Indoles / Q000494:pharmacology; D008297:Male; D010101:Oxygen Consumption / Q000187:drug effects / Q000502:physiology; D011441:Propylthiouracil; D011725:Pyridines / Q000494:pharmacology; D017448:Receptors, Dopamine D2 / Q000819:agonists / Q000378:metabolism*; D012119:Respiration / Q000187:drug effects; D012737:Sex Factors; D017552:Solitary Nucleus / Q000187:drug effects / Q000378:metabolism*; D013974:Thyroxine / Q000097:blood; D014851:Wakefulness / Q000187:drug effects / Q000502:physiology
chemical_list: D018491:Dopamine Agonists; D007211:Indoles; D011725:Pyridines; D017448:Receptors, Dopamine D2; D001971:Bromocriptine; D011441:Propylthiouracil; C071485:carmoxirole; D013974:Thyroxine
keywords: Bromocriptine; Carmoxirole; Control of breathing; Female; Hypothyroidism; Hypoxia