Role of inhibition in respiratory pattern generation.

Postsynaptic inhibition is a key element of neural circuits underlying behavior, with 20-50% of all mammalian (nongranule) neurons considered inhibitory. For rhythmic movements in mammals, e.g., walking, swimming, suckling, chewing, and breathing, inhibition is often hypothesized to play an essential rhythmogenic role. Here we study the role of fast synaptic inhibitory neurotransmission in the generation of breathing pattern by blocking GABA(A) and glycine receptors in the preBötzinger complex (preBötC), a site essential for generation of normal breathing pattern, and in the neighboring Bötzinger complex (BötC). The breathing rhythm continued following this blockade, but the lung inflation-induced Breuer-Hering inspiratory inhibitory reflex was suppressed. The antagonists were efficacious, as this blockade abolished the profound effects of the exogenously applied GABA(A) receptor agonist muscimol or glycine, either of which under control conditions stopped breathing in vagus-intact or vagotomized, anesthetized, spontaneously breathing adult rats. In vagotomized rats, GABA(A)ergic and glycinergic antagonists had little, if any, effect on rhythm. The effect in vagus-intact rats was to slow the rhythm to a pace equivalent to that seen after suppression of the aforementioned Breuer-Hering inflation reflex. We conclude that postsynaptic inhibition within the preBötC and BötC is not essential for generation of normal respiratory rhythm in intact mammals. We suggest the primary role of inhibition is in shaping the pattern of respiratory motor output, assuring its stability, and in mediating reflex or volitional apnea, but not in the generation of rhythm per se.

Uncovering a Failed Pediatric Patient Population in Rural America: A Statewide Analysis of Over 1,000 Dog Bite Injuries.

Pediatric dog bites are prevalent and often devastating. Population-based data on these injuries can aid public health intervention efforts. However, most existing literature comes from single institutions in urban settings. We assess a statewide cohort to compare injury characteristics in urban and rural regions and find predictors for inter-hospital transfer. Data from 1,007 injuries from 2000 to 2015 were analyzed. Patients in rural areas were younger, more likely to be white and low-income, and more likely to receive delayed patient care. Injuries occurring in public settings as opposed to the private residence were more likely to involve males, occur in low-income areas, and involve non-white patients. Patients who required inter-hospital transfer were more likely to require a surgical subspecialist and operative repair. Our population analysis reveals children living in rural areas as a previously unidentified vulnerable patient population that may be suitable targets for public health interventions.