The autonomic nervous system plays an important role in regulating the physiological processes of the human organism under both normal and pathological conditions. Among the techniques used for its assessment, heart rate variability (HRV) has emerged as a simple and non-invasive measure of autonomic impulses, representing one of the most promising quantitative markers of autonomic balance, to assess ANS modulation. HR variations or variability can be measured in time and frequency domains, with specific protocols for each domain. Manual cervical vertebral therapy promotes increased range of motion in the manipulated segment and acts on neurophysiological mechanisms of pain reduction promoting adjustments in spine hypomobility that may be one of the factors that cause an increase in parasympathetic and or sympathetic tone may lead to modulation of cardiac ANS promoting hemodynamic effects on heart rate. Regardless of the type of manual vertebral therapy technique, it is observed that when acting on the cervicothoracic region, both the sympathetic and parasympathetic portion of the ANS are affected causing changes according to the technique and body region activated, certainly, future research is necessary to evaluate , in a greater number of subjects, the influence of the sympathetic and parasympathetic systems on cervical vertebral manipulation techniques.

The term cerebral plasticity covers the possible mechanisms of neuronal reorganization, recruitment of functionally homologous pathways, synaptogenesis, dendritic arborization and activation of secondary areas. Cerebral reorganization still begins in the acute phase after the cortical lesion, with progressive improvement until the stabilization of the condition. Although cortical remodeling is most noticeable during the early stages, changes in brain activity continue until one year after injury. The processes of repair and reorganization of the central nervous system that begin soon after the injury, added to the physiotherapy rehabilitation intensified in the initial phase, will favor the learning or relearning the motor of the patient after the neuronal injury, because the rehabilitation process will happen at the peak of plasticity, thus favoring their motor responses. Several techniques have been used for the recovery of motor function, however there are controversies as to the result in neuroplasticity. The relationship between synaptic efficiency and microglial activation is still not well described in the literature. It is believed that during a specific task, the phagocytic activity of the microglia causes weaker synapses to be eliminated, leading to a greater activation of stronger synapses, thus, early physiotherapy in the early phase may promote the repair and healing process in the damaged areas, as well as, may favor the trophism and plasticity of the remaining neurons. Thus, this work aimed to review on neuro-glial interaction and neuronal plasticity, related to the aspects of early physiotherapy.

Astroglial and microglial activation were analyzed in the ventral tegmental area (VTA) in adult male Wistar rats, after an unilateral striatal 6-hydroxydopamine (6-OHDA) injection. Different doses (8, 4, and 1 microg) of 6-OHDA were injected in the left side of the neostriatum; animals were sacrificed 22 days later. Control animals received an injection of the same volume of the solvent. The tyrosine hydroxylase (TH) positive dopamine cells, the glial fibrillary acidic protein (GFAP) immuno -labeled astrocytes, and the OX42 immunoreactive microglia were visualized by means of immunohistochemistry and quantified by stereologic methods employing the optical dissector and the point intercepts. The number and the density of TH immunoreactive cell bodies were decreased by 45% and 46%, respectively, in the sampled field of the ipsilateral VTA of 8 microg 6-OHDA injected rats. The GFAP immunohistochemistry revealed in the ipsilateral VTA increases the number and density of astroglial cells (154% and 166% of control, respectively) in the rats with a higher dose of the 6-OHDA, and also in the volume fraction of the astroglial processes after 8 microg (41% of control) and 4 microg (24% of control) of 6-OHDA. Increased number (76% of control) and density (77% of control) of OX42 microglial labeled profiles and microglial processes (51% of control) were found in the ipsilateral VTA of the 8 microg 6-OHDA injected animals. These results suggest that the retrograde degeneration of the mesostriatal dopamine pathways, induced by a striatal injection of 6-OHDA, leads to astroglial and microglial reactions in the VTA. The interaction between activated glial cells may be involved in the wounding and repair events in the partial lesioned system, and also in the trophic paracrine responses in the surviving VTA dopamine neurons.

Astroglial and microglial activation was analyzed in adult male Wistar rats after a unilateral striatal injection of different doses (8, 4 and 1 micrograms) of 6-hydroxydopamine (6-OHDA). Control animals received the injection of the same volume of the solvent. The rotational behavior was registered by a rotometer 24 and 72 hours, 7, 10, 14 and 22 days after lesion. Following, animals were sacrificed and the tyrosine hydroxylase (TH) positive dopamine cells, the glial fibrillary acidic protein (GFAP) immunolabeled astrocytes and the OX42 immunoreactive microglia were visualized by mean of immunohistochemistry and quantified by stereologic method employing the optical disector and the point intercepts. The apomorphine (0.5 mg/kg)-induced circling behavior was seen only after 8 micrograms of 6-OHDA from 72 hours postlesion until sacrifice. Decreases of the TH immunoreactive terminals and cell bodies were found in the sampled fields of the striatum and pars compacta of the substantia nigra (SNc), respectively, after 8 and 4 micrograms of 6-OHDA. The GFAP immunohistochemistry revealed increases in the number/density of astroglial cells in the ipsilateral neostriatum (137% of control) and ipsilateral SNc (83% of control) and also in the volumeal fraction of the astroglial processes in the ipsilateral neostriatum (30% of control) and ipsilateral SNc (38% of control) in the rats with higher dose of the neurotoxin. Increases in the number of OX42 microglial labeled profiles and in the volumeal fraction of microglial processes were found in the ipsilateral neostriatum (67% and 27%, respectively, of control) and ipsilateral SNc (100% and 50%, respectively, of control) in the 8 micrograms 6-OHDA injected rats. These results suggest that the retrograde degeneration induced by a intrastriatal injection of a small dose of the 6-OHDA leads to an astroglial and microglial reaction in the nigrostriatal dopamine pathway. The interaction between activated glial cells may be involved in the wounding and repair events in the partial lesioned nigrostriatal system as well as in the paracrine responses to surviving dopamine neurons.