Combined unusual origin and course of the right vertebral artery and right inferior thyroid artery: a case report.

PURPOSE: An unusual unilateral origin and course of the prevertebral part of the right vertebral artery and anomalous course of the right inferior thyroid artery was observed during dissection of the neck of a cadaver. METHODS: An accidental finding in the cadaver within the anatomical dissection was assessed. RESULTS: The right vertebral artery originated a nonstandard from brachiocephalic trunk and travelled in the anterior cervical region, along the longus colli muscle in front of the transverse processes from C7 to C4, and it entered the transverse foramen of C3. During its course, the position of the right inferior thyroid artery varied: it turned medially and passed posterior to the vertebral vessels and later curved inferomedially to its termination. Additionally, the left vertebral artery of the same cadaver arose directly from the subclavian artery and entered the transverse foramen at C6, and the left inferior thyroid artery passed anterior to the vertebral artery. CONCLUSION: Variation in the vertebral artery and inferior thyroid artery alone have been reported, but a combined variation is rare. The anatomical information from this study will be useful during dissection, angiography, endovascular surgery, thyroidectomy and non-invasive procedures in the cervical region.

Is Innervation of the Neuromuscular Junction at the Diaphragm Modulated by sGC/cGMP Signaling?

We previously reported NO/sGC signaling in the upper respiratory pathway, receiving input from the respiratory neurons of the brainstem to phrenic motoneurons in the C3-C6 spinal cord. In order to assess whether innervation of the neuromuscular junction (NMJ) at the diaphragm is modulated by sGC/cGMP signaling, we performed unilateral 8-day continuous ligation of the phrenic nerve in rats. We examined sGCß1 within the lower bulbospinal pathway (phrenic motoneurons, phrenic nerves and NMJs at the diaphragm) and the cGMP level in the contra- and ipsilateral hemidiaphragm. Additionally, we characterized the extent of phrenic nerve axonal degeneration and denervation at diaphragm NMJs. The results of our study show that continuous 8-day phrenic nerve ligation caused a marked increase in sGCß1 (immunoreactivity and the protein level) in the ipsilateral phrenic motor pool. However, the protein sGCß1 level in the phrenic nerve below its ligation and the cGMP level in the ipsilateral hemidiaphragm were evidently decreased. Using confocal analysis we discovered a reduction in sGCß1-IR boutons/synaptic vesicles at the ipsilateral MNJs. These findings are consistent with the marked axonal loss (∼47%) and significant NMJs degeneration in the ipsilateral diaphragm muscle. The remarkable unilateral decrease in cGMP level in the diaphragm and the failure of EMG recordings in the ipsilateral hemidiaphragm muscle can be attributed to the fact that sGC is involved in transmitter release at the diaphragm NMJs via the sGC-cGMP pathway.

Appearance and differentiation of NADPH-d-positive neurons in rat prefrontal cortex following exposure to retinoic acid.

Retinoic acid (RA) is a biologically active form of vitamin A. Teratogenicity has been observed in pregnant mammals exposed to high doses of vitamin A. We investigated the distribution of nitrergic neurons in rat prefrontal cortex (PFC) at developmental stages 7 days to young adulthood under physiological conditions and after prenatal application of all trans-RA. The neurons were studied histochemically using NADPH-diaphorase, which stains neurons dark blue. We found that nitrergic neurons differentiate rapidly and reach structural maturity by the end of the second week of postnatal development. We found that the processes of the neurons of nitrergic neurons of 14-day-old rats in the RA group were shorter than those of the control group. Our findings suggest that excess RA during the prenatal period may influence the development and morphology of NADPH-diaphorase positive neurons, probably by RA-specific receptors in the PFC of 14-day-old rats. RA receptors may be the main effector molecules responsible for the changes of dendrite length induced by all-trans RA. During later development, changes are not observed, probably due to maturation of the nervous system.