Forepaw stimulation

D.G. Buerk, B.M. Ances, J.H. Greenberg, and J.A. Detre, Temporal dynamics of brain tissue nitric oxide during functional forepaw stimulation in rats. Neuroimage 18, 1-9 (2003). 

In a recent study, rats underwent permanent MCA occlusion and functional activation was studied by bilateral forepaw stimulation and MRI 24 h after the insult (Reese et al. 2000). The CBF response was monitored in both hemispheres by using a T2 -sensitive imaging sequence and intravascular bolus of contrast agent. In the non-ischemic hemisphere, a proper activation due to forepaw stimulation was recorded, but on the affected side no response could be elicited. This failure of activation was first attributed to ischemic damage of the somato-... 

During neonatal development, the brain possesses the striking ability to transfer initially lost functions to new, unaffected cortical areas when irreversible lesions prohibit function of the original representation fields - an ability that is still to a lesser degree present in mature brain. This type of plastic response has been studied in rats with a well defined lesion of the somatosensory cortex that was induced 1 day after birth. Six months later functional MRI (fMRI) was performed with a forepaw stimulation paradigm when the animals showed no neurological... 

Hyder F, Behar KL, Martin MA, Blamire AM, Shulman RG (1994) Dynamic magnetic resonance imaging of the rat brain during forepaw stimulation. J Cereb Blood Flow Metab 14 649-655... 

Figure 6 illustrates the hemodynamic responses in rat brain during one trial of left forepaw stimulation. The stimulus interval is plotted in the same figure. The concentration of oxy-hemoglobin was significantly increased during the... 

Fig. 6 EROS of normal rat and cerebral ischemia rat during one trial of left forepaw stimulation...

The acute CNS effects of MDMA administration are mediated by the release of monoamine transmitters, with the subsequent activation of presynaptic and postsynaptic receptor sites.40 As specific examples in rats, MDMA suppresses 5-HT cell firing, evokes neuroendocrine secretion, and stimulates locomotor activity. MDMA-induced suppression of 5-HT cell firing in the dorsal and median raphe involves activation of presynaptic 5-HT1A autoreceptors by endogenous 5-HT.4142 Neuroendocrine effects of MDMA include secretion of prolactin from the anterior pituitary and corticosterone from the adrenal glands 43 Evidence supports the notion that these MDMA-induced hormonal effects are mediated via postsynaptic 5-HT2 receptors in the hypothalamus, which are activated by released 5-HT. MDMA elicits a unique profile of locomotor effects characterized by forward locomotion and elements of the 5-HT behavioral syndrome such as flattened body posture, Straub tail, and forepaw treading.44 6 The complex motor effects of MDMA are dependent on monoamine release followed by activation of multiple postsynaptic 5-HT and DA receptor subtypes in the brain,47 but the precise role of specific receptor subtypes is still under investigation. 

The release of prostaglandins from the cerebral cortex of the anaesthetised cat was first reported by Ramwell and Shaw (1966). The level of release could be increased by stimulation of the contralateral forepaw and by administration of analeptics, suggesting that prostaglandin release might be connected with neuronal activity. 

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