The distribution of nitric oxide synthase-, adenosine deaminase- and neuropeptide Y-immunoreactivity through the entire rat nucleus tractus solitarius: Effect of unilateral nodose ganglionectomy.
The present study has employed immunocytochemistry on free-floating sections of adult rat medulla oblongata to characterise the distribution of nitric oxide synthase- (NOS), adenosine deaminase- (ADA) and neuropeptide Y- (NPY) immunoreactivity (IR) throughout the entire rostro-caudal axis of the nucleus tractus solitarius (NTS). In addition, unilateral nodose ganglionectomy was performed in a group of rats to determine whether any observed immunoreactivity was associated with central vagal afferent terminals. NOS-IR was found throughout the entire NTS, in cells, and both varicose and non-varicose fibres. Furthermore, unilateral nodose ganglionectomy resulted in a clear reduction in NOS-IR (visualised with diaminobenzidine) in a highly restricted portion of the ipsilateral medial NTS. Similarly, ADA- and NPY-containing cells, fibres and terminals were also found throughout the adult rat NTS. However, following unilateral nodose ganglionectomy, there was no apparent reduction in either ADA-IR or NPY-IR on the denervated side of the NTS. These data indicate a role for nitric oxide, purines and neuropeptide Y as neuromodulators within the rat NTS, although only nitric oxide appears to be primarily associated with vagal afferent input. Adenosine deaminase and neuropeptide Y-containing neurons appear to be predominantly postsynaptic to vagal input, although their possible association with vagal afferents cannot be completely excluded.
Department of Pharmacology, Monash University, Clayton, Vic., Australia. Andrew.Lawrence@med.monash.edu.au
A J
AJ
Lawrence
M
M
Castillo-Meléndez
K J
KJ
McLean
B
B
Jarrott
D000243:Adenosine Deaminase / Q000032:analysis*; D000818:Animals; D015171:Ganglionectomy; D007150:Immunohistochemistry; D008297:Male; D009478:Neuropeptide Y / Q000032:analysis*; D019001:Nitric Oxide Synthase / Q000032:analysis*; D052248:Nitric Oxide Synthase Type I; D051381:Rats; D011921:Rats, Inbred WKY; D017552:Solitary Nucleus / Q000737:chemistry*
D009478:Neuropeptide Y; D019001:Nitric Oxide Synthase; D052248:Nitric Oxide Synthase Type I; C496322:Nos1 protein, rat; D000243:Adenosine Deaminase