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Superior laryngeal nerve section abolishes capsaicin evoked chemoreflex in anaesthetized rats

100%

Kaczynska K., Szereda-Przestaszewska M.

Acta Neurobiologiae Experimentalis

2002

vol. 62

issue 1

19-24

Respiratory effects of an intravenous injection of capsaicin were investigated in nine vagotomized and subsequently laryngeally deafferentated, urethane- and chloralose- anaesthetized and spontaneously breathing rats. Bolus injection of capsaicin (5 g/kg) into the right femoral vein induced an expiratory apnoea of 4.23 0.63 s duration (mean SEM). In post-apnoeic breathing, tidal volume increased by 14% from the control level (P<0.05) in all nine rats treated by vagotomy. Section of the superior laryngeal nerves (SLNs) precluded the occurrence of apnoea. Results of this study indicate that in vagotomized rats sensory input from the larynx constitutes an important pathway to the nodose ganglia endowed with capsaicin receptors.

Adaptations to the air breathing in the posterior intestine of the catfish (Corydoras aeneus, Callichthyidae). A histological and ultrastructural study

75%

Podkowa D., Goniakowska-Witalinska L.

Folia Biologica

2002

vol. 50

issue 1-2

69-82

A light and transmission electron microscopic study of the intestine of catfish C. aeneus shows that the anterior part of the intestine is a site of digestion and absorption and its structure is typical of that of other teleostean fishes. However, in this species the thin- walled posterior intestine is adapted to air breathing. In this region mucosa is smooth and lined with respiratory epithelium with capillary network. Several types of cells are observed in the epithelium: flattened respiratory epithelial cells with short microvili, goblet cells, scarce epithelial cells with numerous longer microvilli, and two types of endocrine cells (EC). The solitary brush cells with several long and thick microvilli described here are the first observation of such cells in the gastrointestinal tract of fishes. Bodies of respiratory epithelial cells lie between capillaries. Their cytoplasm, apart from typical organelles contains dense and lamellar bodies, which are a site of accumulation of surfactant. In regions where capillaries are covered by thin cytoplasmic sheets of respiratory epithelial cells, a thin air-blood barrier is formed, thus enabling gas exchange. Epithelial cells with longer microvilli do not participate in the formation of the air-blood barrier and are probably responsible for absorbtion. EC of the closed type are dispersed within the epithelium. Their cytoplasm contains characteristic round or oval dense core vesicles 69 to 230 nm in diameter. The role of EC and brush cells in the regulation of processes related to absorbtion, and to respiration, is disscused.

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1 Acta Neurobiologiae Experimentalis

1 Folia Biologica

2 2002

1 Goniakowska-Witalinska L.

1 Kaczynska K.

1 Podkowa D.

1 Szereda-Przestaszewska M.

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Superior laryngeal nerve section abolishes capsaicin evoked chemoreflex in anaesthetized rats

Adaptations to the air breathing in the posterior intestine of the catfish (Corydoras aeneus, Callichthyidae). A histological and ultrastructural study