Botzinger complex

Respiratory rhythmicity is an emergent property of the RCPG resulting from mutual inhibition of inspiratory and expiratory related neurons. A minimal model due to Duffin [1991] postulated the early-burst inspiratory (I) neurons and Botzinger complex expiratory (E) neurons to be the mutually inhibiting pair. Adaptation of the I neurons (e.g., by calcium-activated potassium conductance) results in sustained relaxation oscillation in the network under constant chemical excitation. Both neuron groups are assumed to have monosynaptic inhibitory projections to bulbospinal inspiratory (Ir) output neurons (Figure 11.3). The model equations are ... 

FIGURE 11.3 A minimal neural network model of RCPG. I and E denote respectively the early-burst inspiratory neurons and Botzinger complex expiratory neurons P is a fictive adaptation neuron S is an excitation neuron or pacemaker cell. Not shown is the bulbospinal output neuron (1 ). Numbers denote connection strengths. (From Masakazu and coworkers [1998]. With permission.)... 

Lipski, J. and Voss, M.D. 1990. Gating of peripheral chemoreceptor input to medullary inspiratory neurons role of Botzinger complex neurons. In H. Acker, A. Trzebski, R.G. O Regan et al. (Eds.), Chemoreceptors and Chemoreceptor Reflexes, pp. 323-329, New York, Plenum Press. 

Smith, J.C., Ellenberger, H.H., BaUanyi, K. et al. 1991. Pre-Botzinger complex a brainstem region that may generate respiratory rhythm in mammals. Science 254 726. 

Solomon IC, Edelman NH, Neubauer JA. Pre-Botzinger complex functions as a central hypoxia chemosensor for respiration in vivo. J Neurophysiol 2000 83 2854—2868. Lipton AJ, Johnson MA, Macdonald T, Lieberman MW, Gozal D, Gaston B. S-nitrosothiols signal the ventilatory response to hypoxia. Nature 2001 413 171-174. Fandrey J. Hypoxia-inducible gene expression. Respir Physiol 1995 101 1-10. Semenza GL. Hypoxia-inducible factor 1 and the molecular physiology of oxygen homeostasis. J Lab Clin Med 1998 131 207-214. 

In addition to the hypoxia-sensitive sympathoexcitatory region, the respiratory-related region located just rostral to the Cl sympathoexcitatory region, the pre-Botzinger complex, is also directly excited by local hypoxia (38). Analogous to the... 

Solomon IC, Edelman NH, Neubauer JA. Pre-Botzinger complex functions as a central hypoxia chemosensor for respiration in vivo. J Neurophysiol 2000 83 2854-2868. 

Johnson SM, Koshiya N, Smith JC. Isolation of the kernel for respiratory rhythm generation in a novel preparation the pre-Botzinger complex island. J Neurophysiol 2001 85 1772-1776. 

Rekling JC, Feldman JL. Pre-Botzinger complex and pacemaker neurons Hypothesized site and kernel for respiratory rhythm generation. Annu Rev Physiol 1998 60 385 05. 

Butera RJ Jr, Rinzel J, Smith JC. Models of respiratory rhythm generation in the pre-Botzinger complex. 11. Populations of coupled pacemaker neurons. J Neurophysiol 1999 81 398-415. 

Connelly CA, Dobbins EG, Feldman JL. Pre-Botzinger complex in cats respiratory neuronal discharge patterns. Brain Res 1992 590 337-340. 

Ramirez JM, Schwarzacher SW, Pierrefiche O, OUvera BM, Richter DW. Selective lesioning of the cat pre-Botzinger complex in vivo eliminates breathing but not gasping. J Physiol 1998 507 895-907. 

Solomon IC, Neubauer JA, Edelman NH. Role of the pre-Botzinger complex in the production of hypoxia-induced gasping. FASEB J 1998 12 A497. 

Solomon IC, Edelman NH. Effects of unilateral and bilateral pre-Botzinger complex lesions on eupneic breathing in vivo. FASEB J 2000 14 A642. 

Gray PA, Janczewski WA, Mellen N, McCrimmon DR, Feldman JL. Normal breathing requires pre-Botzinger complex neurokinin-1 receptor-expressing neurons. Nat Neurosci 2001 4 927-930. 

Solomon IC, Halat TJ, El-Maghrabi R, O Neal MH, 3rd. Differential expression of connexin26 and connexin32 in the pre-Botzinger complex of neonatal and adult rat. J Comp Neurol 2001 440 12-19. 

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