We used pressure plethysmography to study breathing patterns of neonatal and adult @entity35 acutely exposed to elevated levels of @entity515 . Ventilation (VE) increased progressively with increasing inspired @entity515 . The rise in VE was associated with an increase in tidal volume, but not respiratory rate. In all animals studied, the @entity515 sensitivity (determined from the slope of the VE vs. inspired % @entity515 curve) was variable on a day to day basis. Chemosensitivity was high in neonates 1 day after birth (P1) and fell throughout the first week to a minimum at about P8. Chemosensitivity rose again to somewhat higher values in P10 through adult @entity35 . The developmental pattern of these in vivo ventilatory responses was different than individual locus coeruleus (LC) neuron responses to increased @entity515 . The membrane potential (V(m)) of LC neurons was measured using perforated patch ( @entity2379 ) techniques in brain slices. At all ages studied, LC neurons increased their firing rate by approximately 44% in response to @entity520 (10% @entity515 , pH 7.0). Thus the in vivo ventilatory response to @entity2944 was not correlated with the V(m) response of individual LC neurons to @entity520 in neonatal @entity35 . These data suggest that @entity515 sensitivity of ventilation in @entity35 may exist in two forms, a high-sensitivity neonatal (or fetal) form and a lower-sensitivity adult form, with a critical window of very low sensitivity during the period of transition between the two (approximately P8).

Development of in vivo ventilatory and single chemosensitive neuron responses to XXXX in @entity35 .

@entity2944 :: ('MESH:D006935', 'Disease') :: ['hypercapnia'] @entity2379 :: ('MESH:D000666', 'Chemical') :: ['amphotericin B'] @entity515 :: ('CHEBI:29334', 'Chemical') :: ['CO2'] @entity520 :: ('MESH:D000138', 'Disease') :: ['hypercapnic acidosis'] @entity35 :: ('10116', 'Species') :: ['rats']
@entity2944 :: (MESH:D006935,Disease) :: ['hypercapnia']
