Effect of propofol anesthesia on ultrasonographic measurements of the adrenal glands of healthy cats

Although real-time ultrasonography is feasible in awake cats, cats are frequently anesthetized with propofol, if they are uncooperative or during perioperative ultrasonographic examinations. Propofol induces hypotension in cats and may cause venous vasodilation that redistributes blood volume in abdominal organs and organomegaly. In this paper, ultrasonographic adrenal measurements are compared before and during intravenous propofol anesthesia in healthy cats. No significant effect of propofol anesthesia on adrenal size was found, and the observed differences were small and clinically irrelevant. Therefore, it can be concluded that propofol anesthesia does not prevent ultrasonographic diagnosis of adrenomegaly.

Auditory response properties of neurons in the putamen and globus pallidus of awake cats

Several decades of research have provided evidence that the basal ganglia are closely involved in motor processes. Recent clinical, electrophysiological, behavioral data have revealed that the basal ganglia also receive afferent input from the auditory system, but the detailed auditory response characteristics have not yet reported. The present study aimed to reveal the acoustic response properties of neurons in parts of the basal ganglia. We recorded single-unit activities from the putamen (PU) and globus pallidus (GP) of awake cats passively listening to pure tones, click trains, and natural sounds. Our major findings were: 1) responses in both PU and GP neurons were elicited by pure-tone stimuli, whereas PU neurons had lower intensity thresholds, shorter response latencies, shorter excitatory duration, and larger response magnitudes than GP neurons. 2) Some GP neurons showed a suppressive response lasting throughout the stimulus period. 3) Both PU and GP did not follow periodically repeated click stimuli well, and most neurons only showed a phasic response at the stimulus onset and offset. 4) In response to natural sounds, PU also showed a stronger magnitude and shorter duration of excitatory response than GP. The selectivity for natural sounds was low in both nuclei. 5) Nonbiological environmental sounds more efficiently evoked responses in PU and GP than the vocalizations of conspecifics and other species. Our results provide insights into how acoustic signals are processed in the basal ganglia and revealed the distinction of PU and GP in sensory representation.