CERVICAL SPINAL CORD TRANSECTION (SCT) INCREASES GASTRIC COMPLIANCE IN ANESTHETIZED RATS
Abstract:
Spinal cord injury (SCI) can markedly alter the autonomic nervous system’s functions. It
immediately causes autonomic and somatic hypo- or arreflexia, a state known as spinal shock. SCI
determines the enhancement of two gastric reflexes that appear in normal conditions: the receptive
and adaptative reflexes. Furthermore, this study also tried to evaluate the causes that led to such
modifications: either vagal control, nitric oxide (NO)-pathways or intestine-intestinal reflexes. Male
Wistar rats (N=25) were subjected to laminectomy (Sham group) or laminectomy + complete Spinal
Cord Transection (SCT), between C7 and T1 vertebrae under anesthesia (SCT group). Before the
surgery, the rats had water and food ad libitum; after the surgery, rats were fasted for 24 hours, still
having access to water. The next day, all animals were subjected to a catheterism of their right carotid
artery, a tracheostomy and a flexible balloon introduction down to the stomach’s fundix region, also
under anesthesia. Rats were connected to a Power-Lab® system, via a pressure transducer (in order
to measure the arterial pressure – MAP - and the heart rate - HR), and to a modified Plethysmometer
(in order to measure the fundical gastric volume - GV variation). Vagal control was studied via
cervical vagotomy; NO-mediation - via NO synthesis inhibitors (L-NAME); intestinointestinal reflexes
- by using laxatives (Lactulone). Statistical analysis revealed, in some cases, that GV is significantly
(p<0.05) augmented in SCT rats (2,4±0,09; 3,1±0,05; 3,7±0,06 ml) than in Sham (2,2±0,12;
2,9±0,12; 3,3±0,15 ml). Nevertheless, MAP and HR, were subsequently lower (p<0.05) in SCT
(63,5±21,1mm Hg; 227,1±25,2 BPM) than in the control group (88,2±14,4mm Hg; 427,0±19,2 BPM).
In summary, the increase of GV in SCT, seems to involve vagal pathways and/or NO-mediation, but
still not neglecting the colic-gastric reflexes.
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