Differential effects on phrenic output of two dopamine agonists, apomorphine and bromocriptine. 1984

A M Nielsen, and G E Bisgard

Effects of dopamine agonists upon phrenic output were studied in decerebrate, vagotomized, paralyzed, carotid-body denervated dogs. Intravenous administration of dopamine was without effect in these dogs. Apomorphine (APO) increased phrenic minute activity while bromocriptine (BRO) decreased phrenic minute activity following intravenous injection at doses of 100 micrograms/kg for each drug. BRO-induced decreases in phrenic minute activity were associated with decreases in phrenic amplitude; burst frequency remained unchanged. Conversely, APO-induced increases in phrenic minute activity resulted from significant increases in both frequency and amplitude. Both APO and BRO significantly prolonged inspiratory duration and shortened expiratory duration. Responses to APO and BRO were abolished with haloperidol. These results confirm previous evidence for the existence of dopaminergic receptors within the central nervous system, which are inaccessible to exogenous dopamine, and which can alter timing as well as amplitude characteristics of the integrated phrenic neurogram. Both excitation and inhibition of phrenic activity following administration of APO and BRO are mediated by mechanisms within or below the caudal brainstem.

UI MeSH Term Description Entries
D010791 Phrenic Nerve The motor nerve of the diaphragm. The phrenic nerve fibers originate in the cervical spinal column (mostly C4) and travel through the cervical plexus to the diaphragm. Nerve, Phrenic,Nerves, Phrenic,Phrenic Nerves
D011954 Receptors, Dopamine Cell-surface proteins that bind dopamine with high affinity and trigger intracellular changes influencing the behavior of cells. Dopamine Receptors,Dopamine Receptor,Receptor, Dopamine
D012119 Respiration The act of breathing with the LUNGS, consisting of INHALATION, or the taking into the lungs of the ambient air, and of EXHALATION, or the expelling of the modified air which contains more CARBON DIOXIDE than the air taken in (Blakiston's Gould Medical Dictionary, 4th ed.). This does not include tissue respiration ( Breathing
D001971 Bromocriptine A semisynthetic ergotamine alkaloid that is a dopamine D2 agonist. It suppresses prolactin secretion. 2-Bromoergocryptine,Bromocryptin,2-Bromo-alpha-ergocryptine,2-Bromo-alpha-ergokryptine,2-Bromoergocryptine Mesylate,2-Bromoergocryptine Methanesulfonate,2-Bromoergokryptine,Bromocriptin,Bromocriptine Mesylate,CB-154,Parlodel,2 Bromo alpha ergocryptine,2 Bromo alpha ergokryptine,2 Bromoergocryptine,2 Bromoergocryptine Mesylate,2 Bromoergocryptine Methanesulfonate,2 Bromoergokryptine,CB 154,CB154,Mesylate, 2-Bromoergocryptine,Mesylate, Bromocriptine,Methanesulfonate, 2-Bromoergocryptine
D002344 Carotid Body A small cluster of chemoreceptive and supporting cells located near the bifurcation of the internal carotid artery. The carotid body, which is richly supplied with fenestrated capillaries, senses the pH, carbon dioxide, and oxygen concentrations in the blood and plays a crucial role in their homeostatic control. Glomus Caroticum,Bodies, Carotid,Body, Carotid,Caroticum, Glomus,Carotid Bodies
D003655 Decerebrate State A condition characterized by abnormal posturing of the limbs that is associated with injury to the brainstem. This may occur as a clinical manifestation or induced experimentally in animals. The extensor reflexes are exaggerated leading to rigid extension of the limbs accompanied by hyperreflexia and opisthotonus. This condition is usually caused by lesions which occur in the region of the brainstem that lies between the red nuclei and the vestibular nuclei. In contrast, decorticate rigidity is characterized by flexion of the elbows and wrists with extension of the legs and feet. The causative lesion for this condition is located above the red nuclei and usually consists of diffuse cerebral damage. (From Adams et al., Principles of Neurology, 6th ed, p358) Decerebrate Posturing,Decorticate Rigidity,Decorticate State,Rigidity, Decerebrate,Rigidity, Decorticate,Decerebrate Posturings,Decerebrate Rigidity,Decerebrate States,Decorticate Rigidities,Decorticate States,Posturing, Decerebrate,Posturings, Decerebrate,Rigidities, Decorticate,State, Decerebrate,States, Decerebrate
D003714 Denervation The resection or removal of the nerve to an organ or part. Laser Neurectomy,Neurectomy,Peripheral Neurectomy,Radiofrequency Neurotomy,Denervations,Laser Neurectomies,Neurectomies,Neurectomies, Laser,Neurectomies, Peripheral,Neurectomy, Laser,Neurectomy, Peripheral,Neurotomies, Radiofrequency,Neurotomy, Radiofrequency,Peripheral Neurectomies,Radiofrequency Neurotomies
D004285 Dogs The domestic dog, Canis familiaris, comprising about 400 breeds, of the carnivore family CANIDAE. They are worldwide in distribution and live in association with people. (Walker's Mammals of the World, 5th ed, p1065) Canis familiaris,Dog
D006220 Haloperidol A phenyl-piperidinyl-butyrophenone that is used primarily to treat SCHIZOPHRENIA and other PSYCHOSES. It is also used in schizoaffective disorder, DELUSIONAL DISORDERS, ballism, and TOURETTE SYNDROME (a drug of choice) and occasionally as adjunctive therapy in INTELLECTUAL DISABILITY and the chorea of HUNTINGTON DISEASE. It is a potent antiemetic and is used in the treatment of intractable HICCUPS. (From AMA Drug Evaluations Annual, 1994, p279) Haldol
D000200 Action Potentials Abrupt changes in the membrane potential that sweep along the CELL MEMBRANE of excitable cells in response to excitation stimuli. Spike Potentials,Nerve Impulses,Action Potential,Impulse, Nerve,Impulses, Nerve,Nerve Impulse,Potential, Action,Potential, Spike,Potentials, Action,Potentials, Spike,Spike Potential

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