The role of vasoactive intestinal polypeptide and nitric oxide in abdominal surgery induced relaxations of the rat gastric fungus

1999 ◽  
Vol 11 (12) ◽  
pp. A116
Author(s):  
P. J.E. Blommaart ◽  
A. Kodde ◽  
G. N.J. Tytgat
1994 ◽  
Vol 266 (1) ◽  
pp. G31-G39 ◽  
Author(s):  
E. E. Daniel ◽  
C. Haugh ◽  
Z. Woskowska ◽  
S. Cipris ◽  
J. Jury ◽  
...  

This study examined the role of nitric oxide (NO) in tonic inhibition of motor activity in isolated, perfused canine ileal segments. Brief addition of N omega-nitro-L-arginine methyl ester (L-NAME) to the perfusate caused, after a delay, a concentration-dependent persistent increase in tonic and phasic activity of circular muscle. This increased motor activity was prevented or reversed by addition of L- but not D-arginine to the perfusate. Removal of Ca2+ or addition of 10(-7) M omega-conotoxin (GVIA) to the perfusate markedly reduced this response. The motor activity induced by L-NAME was accompanied by loss of distal inhibition and enhanced excitation to low-frequency field stimulation. L-NAME infusion significantly reduced tonic vasoactive intestinal polypeptide (VIP) output, sodium nitroprusside increased VIP output, but L-arginine infusion did not restore VIP output. Atropine (10(-7) M) and/or hexamethonium (10(-4) M) reduced the motor response to L-NAME by 75%. Atropine reduced and hexamethonium nearly abolished VIP output. We conclude that there is tonic Ca(2+)-dependent NO output from perfused intestinal segments dependent on nerves with N-Ca channels, that NO acts to inhibit muscle directly and by inhibiting release of excitatory mediators, and that this output is the primary inhibitory determinant of contractile activity.


2000 ◽  
Vol 129 (1) ◽  
pp. 12-20 ◽  
Author(s):  
M Tonini ◽  
R De Giorgio ◽  
F De Ponti ◽  
C Sternini ◽  
V Spelta ◽  
...  

2021 ◽  
Vol 2 (1) ◽  
Author(s):  
Stuart A Collins ◽  
Ipe Ninan

Abstract The onset of several neuropsychiatric disorders including anxiety disorders coincides with adolescence. Consistently, threat extinction, which plays a key role in the regulation of anxiety-related behaviors, is diminished during adolescence. Furthermore, this attenuated threat extinction during adolescence is associated with an altered synaptic plasticity in the infralimbic medial prefrontal cortex (IL-mPFC), a brain region critical for threat extinction. However, the mechanism underlying the altered plasticity in the IL-mPFC during adolescence is unclear. Given the purported role of vasoactive intestinal polypeptide expressing interneurons (VIPINs) in disinhibition and hence their potential to affect cortical plasticity, we examined whether VIPINs exhibit an adolescence-specific plasticity in the IL-mPFC. We observed an increase in GABAergic transmission and a decrease in excitability in VIPINs during adolescence. Male mice show a significantly higher VIPIN-pyramidal neuron GABAergic transmission compared with female mice. The observed increase in GABAergic transmission and a decrease in membrane excitability in VIPINs during adolescence could play a role in the altered plasticity in the adolescent IL-mPFC. Furthermore, the suppression of VIPIN-mediated GABAergic transmission in females might be relevant to sex differences in anxiety disorders.


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