Respiratory neuroplasticity following carotid body denervation Central and peripheral adaptations

Historically, the role of the carotid bodies in ventilatory control has been understated, but the current view suggests that the carotid bodies （1） provide a tonic, facilitory input to the respiratory network, （2） serve as the major site of peripheral 02 chemoreception and minor contributor to CO2/H＋ chemoreception, and （3） are required for ventilatory adaptation to high altitude. Each of these roles has been demonstrated in studies of ventilation in mammals after carotid body denervation. Following carotid body denervation, many of the compromised ventilatory ＂functions＂ show a time-dependent recovery plasticity that varies in the degree of recovery and time required for recovery. Respiratory plasticity following carotid body denervation is also dependent on species, with contributions from peripheral and central sites/mechanisms driving the respiratory plasticity. The purpose of this review is to provide a summary of the data pointing to peripheral and central mechanisms of plasticity following carotid body denervation. We speculate that after carotid body denervation there are altered excitatory and/or inhibitory neuromodulator mechanisms that contribute to the initial respiratory depression and the subsequent respiratory plasticity, and further suggest that the continued exploration of central effects of carotid body denervation might provide useful information regarding the capacity of the respiratory network for plasticity following neurologic injury in humans.

Taste sensitivity and divergence in host plant acceptance between adult females and larvae of Papilio hospiton

On the island of Sardinia the lepidopteran Papilio hospiton uses Ferula com- munis as exclusive host plant. However, on the small island of Tavolara, adult females lay eggs on Seseli tortuosum, a plant confined to the island. When raised in captivity on Seseli only few larvae grew beyond the first-second instar. Host specificity of lepidopterans is determined by female oviposition preferences, but also by larval food acceptance, and adult and larval taste sensitivity may be related to host selection in both cases. Aim of this work was： （i） to study the taste sensitivity of larvae and ovipositing females to saps of Ferula and Seseli; （ii） to cross-compare the spike activity of gustatory receptor neurons （GRNs） to both taste stimuli; （iii） to evaluate the discriminating capability between the two saps and determine which neural code/s is/are used. The results show that： （i） the spike responses of the tarsal GRNs of adult females to both plant saps are not different and therefore they cannot discriminate the two plants; （ii） larval L-lat GRN shows a higher activity in response to Seseli than Ferula, while the opposite occurs for the phagostimulant neurons, and larvae may discriminate between the two saps by means of multiple neural codes; （iii） the number of eggs laid on the two plants is the same, but the larval growth performance is better on Ferula than Seseli. Taste sensitivity differences may explain the absence of a positive relationship between oviposition preferences by adult females and plant acceptance and growth performance by larvae.

Appraisal of MsepCSP14 for chemosensory functions in Mythimna separata

Chemosensory proteins (CSPs) have great contributions in performing diverse functions in insects. However, physiological appraisal of chemosensory protein genes still remains elusive in insects. We studied expression patterns and binding affinities of MsepCSP14, a chemosensory protein, in Mythimna separata. The distinct functions of MsepCSP14 were validated by employing different molecular techniques. The MsepCSP14 had high resemblance of sequence with chemosensory proteins of other insect family members. The MsepCSP14 expression was higher in antennal tissues of females than other tissues. Fluorescence binding assay validated that binding of nine out of 21 ligands to MsepCSP14 was higher at pH 7.4 than at pH 5.0. Three dimensional modeling (3D) and docking analysis predicted that amino acid residues of MsepCSP14 were involved in binding of compounds, and behavior assay displayed that adults of M. separata considerably responded to four volatiles from compounds demonstrating strong binding ability to MsepCSP14. Results of the present study suggest that MsepCSP14 is likely to mediate chemosensory functions in M. separata.