In this study, we investigated the effects of 192 IgG saporin injections into the medial septal area (MSA), or nucleus basalis magnocellularis (NBM), and combined injections into the MSA and NBM, on water maze and radial arm maze performance in the male rat. The results of the present study reveal a dissociation between the effects of 192 IgG saporin injections into the basal forebrain on the performance of two tasks of spatial learning in the rat. Bilateral injections of 192 IgG saporin into the NBM, MSA or combined MSA/NBM failed to disrupt water maze performance when compared to controls. In contrast, injections of 192 IgG saporin into the MSA, NBM or MSA/NBM induced mild impairments on a radial arm maze task. Overall, the disruption of spatial learning observed in this study was, however, relatively mild compared to deficits in spatial learning reported using less selective lesions of the cholinergic basal forebrain. Consequently, the results of this study suggest that a selective reduction in cholinergic transmission in the basal forebrain is, by itself, insufficient to account for the functional impairments observed in spatial learning in the rat. Although our data do support the use of 192 IgG saporin as a selective cholinergic toxin in the basal forebrain, they further suggests that assessment of spatial learning in the rat following 192 IgG saporin lesions of the basal forebrain in combination with lesions to other neurotransmitter systems, may be a more viable approach to the elucidation of the neuropathological mechanisms that are associated with the cognitive deficits seen in Alzheimer's disease.

A retrospective review of medical records and radiographs of patients receiving anterior cervical discectomy and fusion (ACDF) without anterior plating and with anterior plating was performed. The objective of the study was to determine whether a difference exists in cervical lordotic alignment between subjects undergoing single-level ACDF with and without anterior cervical plating instrumentation for symptomatic cervical disc disease. Collapse or settling of grafted bone into the vertebral endplates with resulting kyphotic deformity of the cervical spine is a commonly described complication of anterior discectomy and fusion. Despite the increasing use of instrumentation for the treatment of cervical spine injuries and degenerative conditions, little is known regarding lordotic alignment of the cervical spine in patients who receive plating instrumentation compared with conventional fusion without plating. Accumulating evidence suggests that plating is superior to non-plating techniques in patients with multiple level cervical disc lesions in regard to fusion, return to work rates, and complication rates; however, little is known about maintenance of lordotic curve alignment in single- and multiple-level procedures. Neutral lateral cervical radiographs of 57 patients who underwent single-level ACDF between 1994 and 1999 with anterior screw plates (n = 26), and conventional single-level fusion without anterior screw plates (n = 21) were retrospectively assessed. Measurements were made on weight-bearing lateral cervical radiographs to assess overall sagittal spinal alignment and intersegmental sagittal alignment at the surgical site before surgery, immediately after surgery, 4 to 12 weeks after surgery, and 12+ months after surgery. The average magnitude of overall lordosis measured between C2 and C7 decreased 4.2 degrees in the non-plated group, while being preserved in the plated group. This finding did not reach statistical significance in the long-term follow-up. At the surgical site, the segmental contribution to lordosis decreased an average 2.5 degrees in the non-plated group versus an increase of 5.67 degrees in the plated group, and this finding was statistically significant between groups measured at all pre- and postoperative visits (p < 0.01). On average, the plating procedure resulted in preserving overall lordosis while increasing the magnitude of segmental lordosis at the surgical site. In comparison, the conventional method resulted in a net loss of overall lordosis and segmental lordosis at the surgical site.

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Behavioral experiments tested the idea that the substance P (SP) innervation of the midbrain central gray (MCG) may be involved in the hormonal induction of sexual receptivity in female rats. SP, a SP antiserum or a reported SP antagonist were injected bilaterally into the MCG in ovariectomized, estrogen-treated females, and the lordosis response was recorded at repeated intervals. In the first experiment, three doses of SP (50, 500 and 1,000 ng/cannula), a single dose of LHRH (50 ng/cannula) or vehicle were given to separate groups of females. All three doses of SP produced a rapid and long-lasting (3 h) increase in lordosis scores in moderately receptive females in tests with either manual stimulation or male rats. This facilitation was similar in latency, magnitude and duration to that produced by LHRH. In the second experiment, the basic findings of experiment 1 were replicated using blind testing. As no dose-response relation was established in experiment 1, a lower dose of SP (10 ng/cannula) was used in addition to doses of 50 and 500 ng/cannula also used in experiment 1. All three doses produced similar long-lasting increases in lordosis scores as in experiment 1. MCG injections of SP also increased lordosis scores in a second series of tests using manual stimulation alone. This demonstrates that the SP-induced facilitation does not depend on an interaction between the injections and stimuli delivered only by the male rat, eg., vaginal stimuli or ultrasonic calls. The question of the importance of endogenous SP for receptivity was examined in experiment 2 using MCG injections of a SP antiserum or the SP analogue, (D-Pro², D-Trp^7,9)-SP, which has been reported to block the excitation of locus coeruleus neurons by SP. The antiserum significantly reduced the group lordosis scores, while the putative antagonist did not. In conclusion, our data support the idea that the SP neurons which innervate the MCG form part of the circuitry controlling the lordosis response.

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