[Function and morphology of the larynx of the domestic guinea pig. An animal model for laryngologic and phoniatric research?].
The present study was undertaken to collect data on fundamental functional and morphological features of the guinea pig larynx using frequency analysis of animal vocalizations and light and scanning electron microscopy. Vocalizations of healthy animals were recorded in an anechoic chamber and were analyzed with short-time fourier transformation (color spectrograms). From the multitude of vocalization patterns produced by the guinea pig, distress squeals were selected as a typical, reproducible, voiced sound. These were stereotyped, upward-frequency modulated, multiharmonic signals with a formant-like structure. The fundamental frequency of this sound rose by about 1.5 octaves and reached up to 6 kHz near the end of the call. The different regions of the endolaryngeal epithelia showed morphological properties that corresponded to proposed functional significance. Keratinized squamous epithelium covered the supraglottic region. The marginal rim of the vocal cord was covered by a very thin epithelium with very flat cells covered with short microvilli. The subepithelial space was filled with loose connective tissue. The subglottic region was covered by respiratory epithelia. Based on these findings, we propose that the larynx of the guinea pig can be used as a model in phoniatric and laryngological research.