Analyses of the Mode of Action of an Alpha-Adrenoceptor Blocker in Substantia Gelatinosa Neurons in Rats.

Daisuke Uta,Tsuyoshi Hattori,Megumu Yoshimura

doi:10.3390/ijms22179636

Abstract

To elucidate why naftopidil increases the frequency of spontaneous synaptic currents in only some substantia gelatinosa (SG) neurons, post-hoc analyses were performed. Blind patch-clamp recording was performed using slice preparations of SG neurons from the spinal cords of adult rats. Spontaneous inhibitory and excitatory postsynaptic currents (sIPSCs and sEPSCs, respectively) were recorded. The ratios of the frequency and amplitude of the sIPSCs and sEPSCs following the introduction of naftopidil compared with baseline, and after the application of naftopidil, serotonin (5-HT), and prazosin, compared with noradrenaline (NA) were evaluated. First, the sIPSC analysis indicated that SG neurons reached their full response ratio for NA at 50 μM. Second, they responded to 5-HT (50 μM) with a response ratio similar to that for NA, but prazosin (10 μM) did not change the sEPSCs and sIPSCs. Third, the highest concentration of naftopidil (100 μM) led to two types of response in the SG neurons, which corresponded with the reactions to 5-HT and prazosin. These results indicate that not all neurons were necessarily activated by naftopidil, and that the micturition reflex may be regulated in a sophisticated manner by inhibitory mechanisms in these interneurons.

Highlights

Life expectancy at birth is estimated to grow year on year according to a recent UnitedNations report [1]
We explored explored the the mechanism mechanismof of the the low low response responserate rateto tonaftopidil naftopidilof ofsIPSCs sIPSCsand andsEPSCs sEPSCsby bycomparing comparing ititto tothe theresponsiveness responsiveness to to NA, 5-HT, and prazosin
Not all substantia gelatinosa (SG) neurons respond to naftopidil, and this may indicate that not all neurons are necessarily activated

Summary

Introduction

Life expectancy at birth is estimated to grow year on year according to a recent UnitedNations report [1]. Life expectancy at birth is estimated to grow year on year according to a recent United. The world’s population is growing older, with persons over the age of 65 being the fastest-growing age group. All countries anticipate an increase in the percentage of older people in their populations in the future. Depresses physical activity, e.g., lower urinary tract function and impaired quality of life is observed in older people with lower urinary tract symptoms (LUTS), which comprise voiding and storage symptoms [2]. Voiding symptoms include slow stream, straining, and intermittency, especially in men with benign prostatic hyperplagia (BPH). Storage symptoms include daytime and nighttime frequency and urgency. Among these urinary symptoms, frequency and urgency are serious for patients [3].

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