moratorium on death sentences by stoning. These agreements benefit not only Iran, but also the EU, supplying it with much needed oil. Such progress could also be accomplished with cooperation with the US, and this could help to end the bitter relations our countries have had.

Strategically, Iran is a gold mine. Iran has one of the Middle East's largest populations with a high degree of support for reform and modernization, and Iran is the main supplier to militant groups such as Hamas and Hezbollah.  The US could potentially boost Iran's economy by lifting current sanctions, and Iran is next-door to the US' current project in the Middle East, Iraq. The bottom line is that our policies toward Iran need to weigh the importance of a political grudge against the possibilities of gaining a new oil-trade partner, cutting off supply lines of anti-Israeli terrorist groups, obtaining valuable co-operation with a soon-to-be nuclear power, and giving our image a much needed improvement in the minds of Moslems. Iran is far too important to ignore,  and, though it will take large concessions on both sides, the benefits outweigh the costs.

Modulation of DRG Neurite Morphology

Brandon Sutton, Research Assistant to Dr. Philip Bonner

Introduction and Background
Motor neurons generate action potentials and propagate them to the axon tips that contain pre-synaptic vesicles. The impulse causes these vesicles to fuse with the cell membrane and release acetylcholine into the synaptic cleft. Here, acetylcholine attaches to the nicotinic acetylcholine receptor, which is a ligand gated Na + channel located on the muscle cell. The opening of this channel ultimately causes the muscle to contract. Because not all of the acetylcholine that has been released is used, it either degrades in the cleft or becomes bound to nicotinic acetylcholine receptors that lie on the pre-synaptic cell.

In motor neurons such as these, it has been observed that when an axon loses its ability to interact with a muscle cell it will branch out in search of a new connection. Once this new connection has been established, the cell can resume its normal function. Axon branching in response to interrupted synaptic transmitter release has been observed after experimental manipulations such as axotomy, inhibition of ac tion potential propagation, and blockade of neurotransmitter release by botulinum toxin type A. It has been suggested that the nerve cell membrane, especially the pre-synaptic portion, contains acetylcholine receptors that act like regulators to tell the cell that transmitter is being released at the synapse.

In my research, I examined a group of neurons that are not motor neurons but are part of the somatosensory system. Dorsal root ganglia (DRG) lie on the sides of the spinal column and connect the peripheral nerves with the spinal cord. In these experiments, DRGs are extracted from 9- and 10-day chick embryos and observed in vitro in response to the addition of alpha conotoxin MII, a highly specific snail-derived protein that binds to the a 3 b 2 nicotinic

acetylcholine receptor. When this binding occurs, acetylcholine is no longer able to bind, therefore the receptor Ca + channel remains closed. Camera lucida drawings were made of the neurons so that axon growth and branching characteristics could be analyzed.

Methodology
These experiments were carried out by first obtaining 9-10 day chick embryos and then extracting them from their shell for surgical manipulation. The dissection of the DRGs was carried out under a light microscope in 10-15mL of calcium-magnesium free (CMF) saline solution. The DRGs were extracted from the embryos and transferred to 1 ml FM culture medium. The ganglia were then pulled through a 26 gauge needle of a 1cc syringe 3-5 times to dissociate the ganglia into single cells. Approximately 0.15 mL of the solution containing the neurons was then placed on 60mm plastic Petri dishes that had previously been coated with ECM Gel (diluted 1:10 with water and dried) and contained 2.5mL of culture medium. Then the dishes were either set aside for controls or 12.5µL of 50nM Alpha conotoxin MII was added directly to the medium. The plates were then placed in an incubator for approximately 24 hrs. and then examined under 400X magnification and the neuron morphologies recorded through camera lucida drawings. The drawings were later analyzed for branching frequencies and neurite lengths.

Conclusions
• Alpha Conotoxin MII increases neurite branch- ing in dorsal root ganglion neurons.

• The specific binding nature of conotoxin MII indicates the a 3 b 2 nicotinic acetylcholine recep- tor is present in DRGs and is possibly being used to monitor and regulate neurite branching of these neurons.

• The total length of the DRG neurites of conotoxin treated cells are much longer than control cells. This indicates that the rate of neu- rite elongation at the growth cones is not significantly inhibited by the increased branch- ing caused by conotoxin.

Future Objectives
The manipulation of morphologies of DRGs and other types of neurons have been accomplished through the use of compounds such as conotoxin and botulinum toxin in in vitro experiments. The next step is to introduce these compounds into a living organism to observe their effects.

Currently, new experiments have started involving the administration of botulinum toxin into an E-13 embryo after a cervical spinal cord crush. The embryo is allowed to develop for three days and then is fixed, sectioned, and stained for observation. Preliminary data suggest that DRGs in embryos treated with botulinum toxin have a greater number of axons entering into the spinal cord than DRGs of control animals. E-16 embryos treated with botulinum toxin had a total number of axons entering the spinal cord from a DRG of 215 ± 11.17, while control embryos had a lower average of 179 ± 49.87.

In addition to the in vivo and in vitro correlation of the effects of botulinum toxin on DRGs, the current experiments are also being used to examine the effects of botulinum toxin on spinal cord neurons around the site of the crush to determine the potential regenerative capabilities of botulinum toxin.