. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. 5' AMP. 50pm Figure 8. Camera lucida drawings of two HRP-filled sensory neurons from the same animal. The cell in the top panel was injected with cAMP approximately 24 h before fixation; the cell in the lower panel was injected with 5'-AMP. In each cell, a single large axon extends from the cell body to the pleural-pedal connective. Because we analyzed only their number, varicosities (arrows) were drawn slightly larger than scale to enhance visibility. Varicosities counted in the cAMP-filled cell were 78 and in the 5'-AMP-nl
. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. 5' AMP. 50pm Figure 8. Camera lucida drawings of two HRP-filled sensory neurons from the same animal. The cell in the top panel was injected with cAMP approximately 24 h before fixation; the cell in the lower panel was injected with 5'-AMP. In each cell, a single large axon extends from the cell body to the pleural-pedal connective. Because we analyzed only their number, varicosities (arrows) were drawn slightly larger than scale to enhance visibility. Varicosities counted in the cAMP-filled cell were 78 and in the 5'-AMP-nlled cell 46. Branch points (arrowheads) counted in the cAMP-filled cell were 32 and in the 5'-AMP-filled cell 24. Not all the branch crossings in these drawings are branch points since these are three-dimensional objects drawn in two dimensions. Some branches ap- pear disconnected as a consequence of the tissue processing procedure. (From Nazif rtu/.. 1991.) labeled with HRP and fixed 24 h after cAMP injection (Fig. 8). Close analysis of the structure of these neurons revealed that both the number of varicosities was doubled and the number of branch points was increased by 50% compared to neurons that had been injected with 5'-AMP, the inactive metabolite of cAMP. The significance of these morphological changes lies in the hypothesis that sensory neurons make more synapses with follower neurons in the pleural ganglion as a result of sensitization. This im- plies that connections between sensory neurons and their followers are strengthened. Additional followers might also be recruited by the formation of new connections. Changes in both of these morphological features could contribute to the enhanced strength of the reflex. In future experiments, it will be interesting to test the role of cAMP in producing other morphological changes such as in- creases in the number, size, and vesicle complement of synaptic active zones (Bailey and Chen, 1983).. Please note that these images ar
Size: 1865px × 1340px
Photo credit: © Library Book Collection / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookauthorlilliefrankrat, booksubjectbiology, booksubjectzoology
