Breathing impairments, such as an alteration in breathing
pattern, dyspnoea, and sleep apnoea, are common health deficits
recognised in Parkinson’s disease (PD). The mechanism that
underlies these disturbances, however, remains unclear. We
investigated the effect of the unilateral damage to the rat
nigrostriatal pathway on the central ventilatory response to
hypercapnia, evoked by administering 6-hydroxydopamine
(6-OHDA) into the right medial forebrain bundle (MFB). The
respiratory experiments were carried out in conscious animals in
the plethysmography chamber. The ventilatory parameters were
studied in normocapnic and hyperoxic hypercapnia before and
14 days after the neurotoxin injection. Lesion with the 6-OHDA
produced an increased tidal volume during normoxia. The
magnified response of tidal volume and a decrease of breathing
frequency to hypercapnia were observed in comparison to the
pre-lesion and sham controls. Changes in both respiratory
parameters resulted in an increase of minute ventilation of the
response to CO2 by 28 % in comparison to the pre-lesion state
at 60 s. Our results demonstrate that rats with implemented
unilateral PD model presented an altered respiratory pattern
most often during a ventilatory response to hypercapnia.
Preserved noradrenaline and specific changes in dopamine and
serotonin characteristic for this model could be responsible for
the pattern of breathing observed during hypercapnia.
Influence of different phosphorus concentrations was studied in four rice varieties (Akhanphou, MTU1010, RP BIO 226, and Swarna) differing in their tolerance to low phosphorus. There was an increase in shoot and root dry mass with the increase in phosphorus concentration. At the low phosphorus concentration at both tillering and reproductive stages, Swarna, followed by Akhanphou, recorded maximum biomass for both roots and shoots, while the minimum was observed in RP BIO 226. Reduction in photosynthetic rate, stomatal conductance, transpiration rate, and internal CO2 concentration at low phosphorus concentrations were observed at both tillering and reproductive stages in all the genotypes. In low phosphorus, maximum photosynthetic rate was found in Swarna followed by Akhanphou. Phosphorus deficiency did not alter the maximum efficiency of PSII photochemistry, however, there was a reduction in effective PSII quantum yield, electron transport rate, and coefficient of photochemical quenching, while the coefficient of nonphotochemical quenching was higher in the low phosphorus-treated plants. Prolonged exposure to excessive energy and failure to utilize the energy in carbon-reduction cycle induced the generation of reactive oxygen species, which affected PSII as indicated by the fluorescence traits. The reduction was less severe in case of Swarna and Akhanphou. The activities of superoxide dismutase, peroxidase, and catalase increased in roots under low phosphorus concentration indicating that photoprotective mechanisms have been initiated in rice plants in response to phosphorus deficiency. Comparatively, Swarna and Akhanphou exhibited a higher biomass, higher photosynthetic rate, and better reactive oxygen species-scavenging ability which conferred tolerance under low phosphorus conditions., N. Veronica, D. Subrahmanyam, T. Vishnu Kiran, P. Yugandhar, V. P. Bhadana, V. Padma, G. Jayasree, S. R. Voleti., and Obsahuje bibliografii