P 1 - 1 9 3 C h a r a c t e r i z a t i o n o f p r o s t a n o i d r e c e p t o r s p r e s e n t o n a d r e n e r g i c n e u r o n s o f p o r c i n e u t e r i n e l o n g i t u d i n a l m u s c l e J i n s h a n C a o l ' 2 , T a k i o K i t a z a

172P

P1-193 Characterization of prostanoid

receptors present on adrenergic neurons of porcine uterine longitudinal muscle Jinshan Caol'2, Takio Kitazawa', Tetsuro Taneike'

'Dept

. Pharmacol., Sch. Vet. Med., Rakuno Gakuen Univ .,

Hokkaido 069-8501, Japan, 2Dept. Basic Vet. Med., College of

Animal Science and Animal Medicine., Inner Mongolia Agriculture Univ., Hohhot, Inner Mongolia 010018, China

We have already demonstrated that cyclooxygenase- prostaglandins (PGs) pathway regulate the spontaneous contractility of porcine uterus through prostanoid receptors . However, location of the receptors (neuron or muscle) is less clear. In this study, presence of neural prostanoid receptors was examined using [ (NA)-loaded porcine uterus.

Electrical field stimulation (EFS, 50V 0.5ms duration, 10Hz for 30s) evoked [3H]-NA release which was abolished by tetrodotoxin, w -conotoxin or Ca'-+-free (EGTA), indicating the neural origin of ['H]-NA release by EFS. PGE2 and PGF2u, but not PGD2, inhibited the EFS-evoked [3H]-NA release. Of selective prostanoid receptor agonists examined, U46619 (TP) and sulprostone (EP,) were effective to decrease the EFS-evoked ['H]-NA release, while fluprostenol (FP), BW245C (DP) and butaprost (EP,) did not change the ['H]-NA release by EFS.

These results indicate that neural prostanoid receptors (EP, and

TP) that regulate NA release are present on adrenergic neurons of

porcine uterine longitudinal muscle. Acknowledgement: this

work was supported by a grant-in-aid for JSPS fellows from

the Ministry of Education, Science, Sports and Culture of Japan.