title: Neural mechanisms underlying respiratory rhythm generation in the lamprey.
abstract: The isolated brainstem of the adult lamprey spontaneously generates respiratory activity. The paratrigeminal respiratory group (pTRG), the proposed respiratory central pattern generator, has been anatomically and functionally characterized. It is sensitive to opioids, neurokinins and acetylcholine. Excitatory amino acids, but not GABA and glycine, play a crucial role in the respiratory rhythmogenesis. These results are corroborated by immunohistochemical data. While only GABA exerts an important modulatory control on the pTRG, both GABA and glycine markedly influence the respiratory frequency via neurons projecting from the vagal motoneuron region to the pTRG. Noticeably, the removal of GABAergic transmission within the pTRG causes the resumption of rhythmic activity during apnea induced by blockade of glutamatergic transmission. The same result is obtained by microinjections of substance P or nicotine into the pTRG during apnea. The results prompted us to present some considerations on the phylogenesis of respiratory pattern generation. They may also encourage comparative studies on the basic mechanisms underlying respiratory rhythmogenesis of vertebrates.
authors.affiliation: Dipartimento di Medicina Sperimentale e Clinica, Sezione Scienze Fisiologiche, Università degli Studi di Firenze, Viale G.B. Morgagni 63, 50134 Firenze, Italy. Electronic address: fulvia.bongianni@unifi.it.
authors.forename: Fulvia
authors.initials: F
authors.lastname: Bongianni
authors.affiliation: Dipartimento di Medicina Sperimentale e Clinica, Sezione Scienze Fisiologiche, Università degli Studi di Firenze, Viale G.B. Morgagni 63, 50134 Firenze, Italy.
authors.forename: Donatella
authors.initials: D
authors.lastname: Mutolo
authors.affiliation: Dipartimento di Medicina Sperimentale e Clinica, Sezione Scienze Fisiologiche, Università degli Studi di Firenze, Viale G.B. Morgagni 63, 50134 Firenze, Italy.
authors.forename: Elenia
authors.initials: E
authors.lastname: Cinelli
authors.affiliation: Dipartimento di Medicina Sperimentale e Clinica, Sezione Scienze Fisiologiche, Università degli Studi di Firenze, Viale G.B. Morgagni 63, 50134 Firenze, Italy.
authors.forename: Tito
authors.initials: T
authors.lastname: Pantaleo
mesh_terms: D000818:Animals; D005075:Biological Evolution; D001933:Brain Stem / Q000033:anatomy & histology / Q000502:physiology*; D063226:Central Pattern Generators / Q000033:anatomy & histology / Q000502:physiology*; D007798:Lampreys / Q000033:anatomy & histology / Q000502:physiology*; D012125:Respiratory Center / Q000033:anatomy & histology / Q000502:physiology*; D012143:Respiratory Physiological Phenomena
keywords: Control of breathing; Evolution of breathing; GABA(A) and glycine receptors; Glutamatergic transmission; Respiratory rhythm generation