Presynaptic inhibitory action of adenosine on neuromuscular transmission in the canine cavernous carotid artery.

نویسندگان

  • S Fujiwara
  • N F Kassell
  • T Sasaki
  • M Yamashita
  • M Zuccarello
چکیده

We investigated the effect of adenosine on neurogenic contraction of the canine cavernous carotid artery, using an isometric tension recording device and transmural nerve stimulation. Adenosine, in concentrations under 10(-5)M, had no relaxing effect on the contractions produced by high [K]o solution or 10(-5)M norepinephrine. Transmural nerve stimulation (stimulus: 1 msec duration, 100V intensity) evoked a frequency-dependent contraction, which was abolished by 3 X 10(-7)M tetrodotoxin. Adenosine in concentrations of 10(-6)M and 10(-5)M, inhibited the neurogenic contraction at each frequency, more so in the low frequency range. This inhibitory effect of adenosine was significantly antagonized by 10(-5)M theophylline. Pretreatment with 2 X 10(-8)M dipyridamole had no effect on neurogenic contractions, but augmented the inhibitory effect of adenosine. 10(-5)M theophylline did not augment the neurogenic contractions. The findings that both dipyridamole and theophylline failed to affect the neurogenic contractions in the absence of adenosine suggests that the presynaptic autoinhibition mechanism of adenosine may not be involved in neuromuscular transmission in this tissue. These results suggest that there is a presynaptic adenosine receptor in the nerve terminal which inhibits the release of neurotransmitter in canine cavernous carotid artery. It is also probable that the vasodilating effect of adenosine in the cavernous carotid artery is mainly due to its inhibitory effect on neurotransmission rather than to a direct relaxing effect on smooth muscle.

برای دانلود رایگان متن کامل این مقاله و بیش از 32 میلیون مقاله دیگر ابتدا ثبت نام کنید

ثبت نام

اگر عضو سایت هستید لطفا وارد حساب کاربری خود شوید

منابع مشابه

Response to Mutafova-Yambolieva and Sanders.

TO THE EDITOR: My research team and I appreciate the thoughts of Dr. Violetta Mutafova-Yambolieva and Prof. Kenton M. Sanders (VMY-KMS; Ref. 14a) to enhance awareness for our recent paper on -nicotinamide adenine dinucleotide ( -NAD) (17). We agree fully with VMY-KMS that roles for purinergic neurotransmission in the gastrointestinal tract are multiple and can be controversial. Major findings i...

متن کامل

INFLUENCE OF ENDO THELIUM REMOVAL AND LNAME ON RESPONSES OF RAT COMMON CAROTID ARTERY TO α-ADRENOCEPTOR AGONISTS

In this study we investigated the effects of endothelium removal and L-NAME on responses to α-adrenoceptor agonists. Male Wistar rats were killed by overdose with pentobarbitone sodium, after which the left and right common carotid arteries were removed. Rings of arteries 3-4 mm in length were cut from each vessel and then mounted in 10 mL isolated organ bath, bathed in Krebs maintained at ...

متن کامل

Neuromuscular transmission modulation by adenosine upon aging.

In infant rats adenosine A(2A) receptor-mediated modulation of neuromuscular transmission predominates over A1 receptor-mediated neuromodulation. We investigated whether aging affects this A(2A)/A(1) receptor balance. Evoked (EPPs) and miniature end plate potentials (MEPPs) were recorded from single fibers of (weeks-old) infant (3-4), young adult (12-16), older (36-38), and aged (80-90) male ra...

متن کامل

Treatment of traumatic trigeminal-cavernous fistula by coil embolization and compression of carotid artery.

We report a case of a traumatic cavernous fistula supplied by a persistent primitive trigeminal artery. The process of treatment was unique in this case. Fistula was subcompletely occluded by coiling from primitive trigeminal artery. Residual fistula was helped to form thrombosis by compression of the carotid artery with hand in the procedure. Long-term follow-up was satisfactory. Traumatic cav...

متن کامل

Adenosine A1 receptor-mediated presynaptic inhibition of GABAergic transmission in immature rat hippocampal CA1 neurons.

In the mechanically dissociated rat hippocampal CA1 neurons with native presynaptic nerve endings, namely "synaptic bouton" preparation, the purinergic modulation of spontaneous GABAergic miniature inhibitory postsynaptic currents (mIPSCs) was investigated using whole-cell recording mode under the voltage-clamp conditions. In immature neurons, adenosine (10 microM) reversibly decreased GABAergi...

متن کامل

ذخیره در منابع من


  با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید

عنوان ژورنال:
  • Stroke

دوره 17 2  شماره 

صفحات  -

تاریخ انتشار 1986