alpha-Adrenergic and cholinergic receptor agonists modulate voltage-gated Ca2+ channels

We investigated the effect of alpha-adrenergic and cholinergic receptor agonists on Ca2+ current in adult rat trigeminal ganglion neurons using whole-cell patch clamp methods. The application of acetylcholine, carbachol, and oxotremorine (50 muM each) produced a rapid and reversible reduction of the Ca2+ current by 17+/-6%, 19+/-3% and 18+/-4%, respectively. Atropine, a muscarinic antagonist, blocked carbachol-induced Ca2+ current inhibition to 3 +/- 1%. Norepinephrine (50 muM) reduced Ca2+ current by 18 +/- 2%, while clonidine (50 muM), an alpha2-adrenergic receptor agonist, inhibited Ca2+ current by only 4 +/- 1%. Yohimbine, an alpha2-adrenergic receptor antagonist, did not block the inhibitory effect of norepinephrine on Ca2+ current, whereas prazosin, an alpha1-adrenergic receptor antagonist, attenuated the inhibitory effect of norepinephrine on Ca2+ current to 6 +/- 1%. This pharmacology contrasts with alpha2-adrenergic receptor modulation of Ca2+ channels in rat sympathetic neurons, which is sensitive to clonidine and blocked by yohimbine. Our data suggest that the modulation of voltage dependent Ca2+ channel by norepinephrine is mediated via an alpha1-adrenergic receptor. Pretreatment with pertussis toxin (250 ng/ml) for 16 h greatly reduced norepinephrine- and carbachol-induced Ca2+ current inhibition from 17 +/- 3% and 18 +/- 3% to 2 +/- 1% and 2 +/- 1%, respectively. These results demonstrate that norepinephrine, through an alpha1-adrenergic receptor, and carbachol, through a muscarinic receptor, inhibit Ca2+ currents in adult rat trigeminal ganglion neurons via pertussis toxin sensitive GTP-binding proteins.

Clinical Analysis of Long Bone Fracture Occurring in Chronic Patients with Spinal Cord Injury / 대한정형외과학회잡지

During the rehabilitation period, traumatic fracture of the lower extremity in chronic spinal cord injured patients may be occur frequently. In the past, conservative treatment with pillow or plaster splinting was advocated by many clinician, but its treatment is still controversial. This paper presents our experience with fracture of 20 patients(5.7%) of total 350 patients who had spinal cord injuries from Jan. 1980 to Mar. 1987 at Korea Veterans Hospital. The results were as follow. 1. The incidence of fracture was not related to age, sex, type and duration of spinal cord injury. 2. The most common cause of fracture was insignificant trauma(94%). 3. The distribution of fracture was in the following order of frequency;supracondyle of femur (20%), shaft of femur (20%), shaft of tibis (16%). 4. The methods of treatment-Twenty cases were treated by conservative treatment and eleven cases were treated by operative treatment in following order; paster splint with well padded; 9 cases (20%), pillow splint; 4 eases (13%), plate and screw; 3 cases (10%). 5. Total 11 cases of complications were 8 cases in conservative treatment and 3 cases in operative treatment. 6. The duration of bone union was average 10 weeks in nonoperative treatment and average 10.2 weeks in operative treatment. Treatment should strive to achieve fracture healing with minimal danger to the patient and should cause little or no interfrence with patient's daily routine.