title: In adult female hamsters hypothyroidism stimulates D1 receptor-mediated breathing without altering D1 receptor expression.
abstract: Hypothyroidism affects cardiopulmonary regulation and function of dopaminergic receptors. Here we evaluated effects of 5 months of hypothyroidism on dopamine D1 receptor modulation of breathing in female hamsters using a D1 receptor antagonist SCH 23390. Euthyroid hamsters (EH) served as controls. Results indicated that hypothyroid female hamsters (HH) exhibited decreased body weights and minute ventilation (VE) following hypoxia due to decreased frequency of breathing (F). Moreover, SCH 23390 administration in HH increased VE by increasing tidal volume during exposure to air, hypoxia and following hypoxia. Relative to vehicle, SCH 23390 treatment decreased body temperature and hypoxic VE responsiveness in both groups. In EH, SCH 23390 decreased F in air, hypoxia and post hypoxia, and VE during hypoxia trended to decrease (P=0.053). Finally, expression of D1 receptor protein was not different between the two groups in any region evaluated. Thus, hypothyroidism in older female hamsters affected D1 receptor modulation of ventilation differently relative to euthyroid animals, but not expression of D1 receptors.
authors.affiliation: Division of Basic Biomedical Sciences, Sanford School of Medicine of the University of South Dakota, 414 East Clark St., Vermillion, SD 57069, USA. 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, USA.
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, USA.
authors.forename: Harold D
authors.initials: HD
authors.lastname: Schultz
mesh_terms: D000818:Animals; D001552:Benzazepines / Q000494:pharmacology; D015153:Blotting, Western; D001831:Body Temperature / Q000187:drug effects / Q000502:physiology; D001835:Body Weight / Q000502:physiology; D002245:Carbon Dioxide / Q000378:metabolism; D004195:Disease Models, Animal; D018492:Dopamine Antagonists / Q000494:pharmacology; D005260:Female; D007037:Hypothyroidism / Q000503:physiopathology*; D008647:Mesocricetus; D010101:Oxygen Consumption / Q000187:drug effects / Q000502:physiology; D011441:Propylthiouracil; D017447:Receptors, Dopamine D1 / Q000037:antagonists & inhibitors / Q000378:metabolism*; D012119:Respiration / Q000187:drug effects; D013990:Tidal Volume / Q000187:drug effects / Q000502:physiology
chemical_list: D001552:Benzazepines; D018492:Dopamine Antagonists; D017447:Receptors, Dopamine D1; C534628:SCH 23390; D002245:Carbon Dioxide; D011441:Propylthiouracil
keywords: D1 receptor expression; Female; Hypothyroidism; Hypoxia; Ventilation