The caudal nucleus tractus solitarius (cNTS): 1) receives direct afferent inputs from
the peripheral baro- and chemo- receptors; 2) contains neurons directly responsive
to CO2 (central chemoreceptors); 3) provides excitatory drive to the neurons in the caudal
ventrolateral medulla; 4) is a critical region regulating both baro- and chemo- reflexes,
and the set-point of arterial pressure. We hypothesize that transgenic ‘silencing’
of Phox2b-expressing neurons in the cNTS will reduce both respiration and arterial
pressure at rest and in response to hypercapnia. We acutely and specifically ‘silenced’
Phox2b-expressing neurons in the cNTS by using a lentiviral vector, PRSx8-AlstR-EGFP-LV,
that includes the Drosophila allatostatin receptor under the control of a Phox2b specific promoter (PRSx8). We
injected the vector into the cNTS of anesthetized male rats (60–90 g) bilaterally & allowed 3–4 weeks for the AlstR-eGFP expression. We then studied the changes of ventilation, arterial
pressure, heart rate, and metabolic rate in air and steady-state 7% CO2 before and after ‘silencing’ Phox2b-expressing neurons in the cNTS by i.c.v. injection
of allatostatin (2 mM, 10ul) in conscious rats. Allatostatin-induced ‘silencing’ of transfected cNTS
Phox2b-expressing neurons: 1) significantly reduced VE/VO2 at rest in wakefulness (~6%; P<0.05; N=8) and in response to hypercapnia in both wakefulness and NREM sleep (~30% P<0.001); 2) decreased arterial pressure in both air and hypercapnia with significance
at 7%CO2 in wakefulness (~7%, P<0.05; N=5). We conclude that Phox2b-expressing neurons in the cNTS region have ongoing discharge
and contribute to both the control of ventilation and arterial pressure at rest and
in response to hypercapnia.
To read this article in full you will need to make a payment
Purchase one-time access:
Academic & Personal: 24 hour online accessCorporate R&D Professionals: 24 hour online accessOne-time access price info
- For academic or personal research use, select 'Academic and Personal'
- For corporate R&D use, select 'Corporate R&D Professionals'
Subscribe:
Subscribe to Autonomic Neuroscience: Basic and ClinicalAlready a print subscriber? Claim online access
Already an online subscriber? Sign in
Register: Create an account
Institutional Access: Sign in to ScienceDirect
Article info
Identification
Copyright
© 2010 Published by Elsevier Inc.