Role of midbrain in the control of breathing in anuran amphibians

Abstract

Gargaglioni LH, Meier JT, Branco LG, Milsom WK. Role of midbrain in the control of breathing in anuran amphibians. Am J Physiol Regul Integr Comp Physiol 293: R447-R457, 2007. First published April 9, 2007; doi:10.1152/ajpregu.00793.2006.-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.control of ventilation; central nervous system; mesencephalon; frog; Rana catesbeiana IN ALL VERTEBRATES, THE MIDBRAIN links the sensory, motor, and integrative components of the pons and medulla with those of the forebrain. The midbrain contains three major regions: the tectum, the tegmentum, and the isthmus. These regions contain nuclei intrinsic to each, as well as ascending and descending fiber tracts that pass through them (2

Excitatory and inhibitory effects of opioid agonists on respiratory motor output produced by isolated brainstems from adult turtles (Trachemys)

“…Episodic breathing is expressed in fish, amphibians, reptiles, and some mammals under certain conditions (Milsom, 1991). Factors that regulate or modulate episodic breathing include chemosensory and mechanosensory inputs (Kinkead and Milsom, 1997; Reid et al, 2003) and central structures rostral to the brainstem (Kinkead et al, 1997; Milsom et al, 1997; Reid et al, 2000; Gargaglioni et al, 2007). In ectothermic vertebrates, the capacity for episodic breathing is contained within the isolated brainstems of tadpoles (Straus et al, 2000), bullfrogs (Kinkead et al, 1994; Reid and Milsom, 1998), and turtles (Douse and Mitchell, 1990; Johnson et al, 1998).…”

Respiratory pattern in midline-lesioned brainstems and hemibrainstems from adult turtles

“…In frogs, episodic breathing appears to be regulated or modulated by chemosensory and mechanosensory inputs (Kinkead and Milsom, 1997), structures rostral to the brainstem (Kinkead et al, 1997; Milsom et al, 1997; Reid et al, 2000; Gargaglioni et al, 2007), and structures within the brainstem during GABA B receptor blockade (Straus et al, 2000). In contrast, very little is known about mechanisms underlying episodic discharge in turtles other than the fact that some isolated turtle brainstems produce episodic cranial nerve motor bursts (Douse and Mitchell, 1990; Johnson et al, 1998).…”

A spatial and cellular distribution of neurotropic virus infection in the mouse brain revealed by fMOST and single cell RNA-seq

“…Accumulating evidence suggest that pontine nuclei, including Kölliker–Fuse (K-F) and parabrachial (PB) nuclei comprise the pontine respiratory group (PRG), which regulates the inspiratory-expiratory phase transition 31, 32 . Other studies report that neurons in the superior colliculus (SC) 33 , RN 33 , and intermediate reticular nucleus (IRN) 34 also influence the respiratory cycle. In our study we showed that the PB, SC, RN and IRN were extensively infected by RABV regardless of the infection route (Figure 3), suggesting that the abnormal breathing may be related to the neuronal damage caused by RABV infection in these nuclei.…”