Role of midbrain in the control of breathing in anuran amphibians.
The present study was designed to explore systematically the midbrain of unanesthetized, decerebrate anuran amphibians (bullfrogs), using chemical and electrical stimulation and midbrain transections to identify sites capable of exciting and inhibiting breathing. Ventilation was measured as fictive motor output from the mandibular branch of the trigeminal nerve and the laryngeal branch of the vagus nerve. The results of our transection studies suggest that, under resting conditions, the net effect of inputs from sites within the rostral half of the midbrain is to increase fictive breathing frequency, whereas inputs from sites within the caudal half of the midbrain have no net effect on fictive breathing frequency but appear to act on the medullary central rhythm generator to produce episodic breathing. The results of our stimulation experiments indicate that the principal sites in the midbrain that are capable of exciting or inhibiting the fictive frequency of lung ventilation, and potentially clustering breaths into episodes, appear to be those primarily involved in visual and auditory integration, motor functions, and attentional state.
Gargaglioni
Luciane H
LH
Departamento de Morfologia e Fisiologia Animal, Faculdade de Ciências Agrárias e Veterinárias, Universidade Estadual Paulista Júlio de Mesquita Filho, Via de acesso Paulo Donato Castellane s/n, 14870-000 Jaboticabal, SP, Brazil. lucihel@fcav.unesp.br
Meier
Janice T
JT
Branco
Luiz G S
LG
Milsom
William K
WK
D000818:Animals; D001369:Axons / Q000502:physiology; D003655:Decerebrate State / Q000503:physiopathology*; D004558:Electric Stimulation; D005260:Female; D018698:Glutamic Acid / Q000008:administration & dosage / Q000494:pharmacology; D007830:Larynx / Q000502:physiology; D008168:Lung / Q000502:physiology; D008297:Male; D008526:Medulla Oblongata / Q000502:physiology; D008636:Mesencephalon / Q000187:drug effects / Q000502:physiology*; D008845:Microinjections; D011892:Rana catesbeiana; D015656:Respiratory Mechanics / Q000187:drug effects / Q000502:physiology*; D013268:Stimulation, Chemical; D013477:Superior Colliculi / Q000502:physiology; D014276:Trigeminal Nerve / Q000502:physiology; D014630:Vagus Nerve / Q000502:physiology
D018698:Glutamic Acid