A PHYSIOLOGICAL UNDERSTANDING ON THE CONCEPT OF ALOCHAKA PITTA

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1 Review Article International Ayurvedic Medical Journal ISSN: A PHYSIOLOGICAL UNDERSTANDING ON THE CONCEPT OF ALOCHAKA PITTA Kamath Nagaraj Assistant, Professor, Department of Shareera Kriya, Karnataka Ayurveda Medical College, Mangalore ; Karnataka, India Corresponding author: nagaraj.kamath1989@gmail.com ABSTRACT Dosha, Dathu, Mala together forms the basis of the body. The balance of these entities represents the healthy state and imbalance will cause various diseases. By mentioning the various Sthana of the each Dosha the different function performed by individual Dosha in different sites has been emphasised. The sub-types of Dosha, its location and function have also been mentioned. There are five types of Pitta namely Pachaka, Ranjaka, Sadhaka, Alochaka, Brajaka. The Visesha Sthana of Alochaka Pitta is said to be Akshi. The main function of Alochaka Pitta is said to be Rupa Grahana i.e responsible for sense of vision. Photoreceptors are specialized cells that begin the process by which light rays are ultimately converted to nerve impulses. There are two types of photoreceptors: rods and cones. Rods allow us to see in dim light, such as moonlight. Because rods do not provide color vision, in dim light we can see only black, white, and all shades of gray in between. Brighter lights stimulate cones, which produce color vision. In the human retina, there are four different opsins, three in the cones and one in the rods (rhodopsin). Small variations in the amino acid sequences of the different opsins permit the rods and cones to absorb different colors (wavelengths) of incoming light. Photopigments respond to light in the cyclical process The functions of Alochaka Pitta can be related to the functions of photo-pigments, phyto chemicals and neurotransmitters which are responsible for the sense of vision. Keywords: Alochaka, Pitta, Shareera, Kriya, Photo-pigments, Neurotransmitters INTRODUCTION The individual is an epitome of the universe. All the material & spiritual phenomenon of the universe are present in the individual. Similarly all those resent in the individual are also contained in the universe. [1] Originating in cosmic consciousness, this wisdom was intuitively received in the hearts of the ancient scholars. They perceived that consciousness was energy manifested into the five basic principles or elements. Man is microcosm of the nature and so the five basic elements present in all matter also exists within each individual. Thus out of the womb of the five elements, all matter is born. The five basic elements exist in all matter. Water provides the classic example: - the solids of iced water are manifestation of the Prithvi Mahabhuta (earth principle). Latent heat in the ice (Agni) How to cite this URL:. International Ayurvedic medical Journal {online} 2016 {cited 2016 May} Available from:

2 904 liquefies it, manifesting into Jala Mahabhuta (water principle). And then eventually it turns into steam expressing the Vayu Mahabhuta (air principle) the steam disappears into Akasha or space. [2] Bhuta is that which is not born out of something, but out of which something is born. It is the material cause of substances in the world. When we say Bhuta we mean that subtle level of existence, whereas Mahabhuta refers to gross level of existence. [3] Panchikarana is the process through which invisible Bhutas combine with each other and form the visible Mahabhutas in such a way that all Bhutas are present together in each Drisya Bhuta in varying degrees of predominance. Thus in the physical world everything is a combination of Pancha Mahabhutas & we cannot see them independently. [4] Dosha, Dathu, Mala together form the basis of the body. [5] The balance of these entities represents the healthy state and imbalance will cause various diseases. [6] In normalcy, Dosha will be performing their own functions and individual Dosha will be having their own specific site. By mentioning the various Sthana of the each Dosha the different function performed by individual Dosha in different sites has been emphasised. The sub-types of Dosha, its location and function have also been mentioned. [7] Regarding the Sthana of various Dosha authors have different opinion. Later authors have added some more Sthana of Dosha. For example, ears among the location of Vata; umbilicus, eyes and skin among the location of Pitta; Kloma, nose, tongue among the location of Kapha. [8] There are five types of Pitta namely Pachaka, Ranjaka, Sadhaka, Alochaka, Brajaka. The Visesha Sthana of Alochaka Pitta is said to be Akshi. The main function of Alochaka Pitta is said to be Rupa Grahana i.e responsible for sense of vision. [9] Brief Physio- anatomical understanding of the eye with reference to vision is necessary to understand physiology of Alochka Pitta. The adult eyeball measures about 2.5cm in diameter. Of its total surface area, only the anterior one-sixth is exposed; the remainder is recessed and protected by the orbit, into which it fits. Anatomically, the wall of the eyeball consists of three layers Fibrous tunic, vascular tunic and retina. The fibrous tunic is the superficial coat of the eyeball and consists of anterior cornea and posterior sclera. The cornea is transparent so as to allow the light to pass and fall over the retina. Sclera, the white of the eye is more rigid and gives shape to the eyeball and protects its inner parts. The vascular tunic consists of three parts, choroid, ciliary body and iris. Choroid is the most vascularised part and it lines most of the internal surface of the sclera. It also possesses melanocytes and is brown black in appearance. Ciliary body also has the same appearance as that of the choroid. It has ciliary processes and muscles, which alters the shape of lens, adapting it for near and far vision. The iris, coloured portion of the eyeball suspended between cornea and lens. Retina, inner coat of the eyeball has two layers pigment layer and neural layer. Pigmented layer is located between choroid and neural layer of retina. Neural layer of retina is a multilayered outgrowth of the brain that processes visual data extensively before sending nerve impulses into axons that form optic nerve. [10] The third and inner layer of the eyeball, the retina, lines the posterior three-quarters of the eyeball and is the beginning of the visual pathway. The anatomy of this layer can be viewed with an ophthalmoscope, an instrument that shines light into the eye and allows an observer to peer through the pupil, providing a magnified image of the retina

3 905 and its blood vessels as well as the optic (II) nerve. The surface of the retina is the only place in the body where blood vessels can be viewed directly and examined for pathological changes, such as those that occur with hypertension, diabetes mellitus, cataracts, and age-related macular disease. Several landmarks are visible through an ophthalmoscope. The optic disc is the site where the optic (II) nerve exits the eyeball. Photoreceptors are specialized cells that begin the process by which light rays are ultimately converted to nerve impulses. There are two types of photoreceptors: rods and cones. Each retina has about 6 million cones and 120 million rods. Rods allow us to see in dim light, such as moonlight. Because rods do not provide color vision, in dim light we can see only black, white, and all shades of gray in between. Brighter lights stimulate cones, which produce color vision. Three types of cones are present in the retina: (1) blue cones, which are sensitive to blue light, (2) green cones, which are sensitive to green light, and (3) red cones, which are sensitive to red light. Color vision results from the stimulation of various combinations of these three types of cones. Most of our experiences are mediated by the cone system, the loss of which produces legal blindness. A person who loses rod vision mainly has difficulty seeing in dim light and thus should not drive at night. From photoreceptors, information flows through the outer synaptic layer to bipolar cells and then from bipolar cells through the inner synaptic layer to ganglion cells. The axons of ganglion cells extend posteriorly to the optic disc and exit the eyeball as the optic (II) nerve. [11] All photopigments associated with vision contain two parts: a glycoprotein known as opsin and a derivative of vitamin A called retinal. Vitamin A derivatives are formed from carotene, the plant pigment that gives carrots their orange color. Good vision depends on adequate dietary intake of carotene-rich vegetables such as carrots, spinach, broccoli, and yellow squash, or foods that contain vitamin A, such as liver. Retinal is the light-absorbing part of all visual photopigments. In the human retina, there are four different opsins, three in the cones and one in the rods (rhodopsin). Small variations in the amino acid sequences of the different opsins permit the rods and cones to absorb different colors (wavelengths) of incoming light. Photopigments respond to light in the following cyclical process: In darkness, retinal has a bent shape, called cis-retinal, which fits snugly into the opsin portion of the photopigment. When cis-retinal absorbs a photon of light, it straightens out to a shape called trans-retinal. This cisto-trans conversion is called isomerization and is the first step in visual transduction. After retinal isomerizes, several unstable chemical intermediates form and disappear. These chemical changes lead to production of a receptor potential. In about a minute, trans-retinal completely separates from opsin. The final products look colorless, so this part of the cycle is termed bleaching of photopigment. An enzyme called retinal isomerase converts trans-retinal back to cis-retinal. The cis-retinal then can bind to opsin, reforming a functional photo pigment. This part of the cycle resynthesis of a photo pigment is called regeneration. [12] The pigmented layer of the retina adjacent to the photoreceptors stores a large quantity of vitamin A and contributes to the regeneration process in rods. The extent of rhodopsin regeneration decreases drastically if the retina detaches from the pigmented layer. Cone photopigments regenerate much more quickly than the rhodopsin in rods and are less dependent on the pigmented layer. After complete bleaching, regeneration of half of the rhodopsin takes 5 minutes; half of the cone photopigments regenerate in only 90 seconds. Full regeneration of bleached rhodopsin takes 30 to 40 minutes. The absorption of light and isomerization of retinal initiates chemical changes in the photoreceptor outer segment that lead to production of a receptor potential. To under-

4 906 stand how the receptor potential arises, however, we first need to examine the operation of photoreceptors in the absence of light. In darkness, sodium ions (Na) flow into photoreceptor outer segments through ligand-gated Na_ channels. The ligand that holds these channels open is cyclic GMP (guanosine monophosphate) or cgmp. The inflow of Na, called the dark current, As a result, in darkness the membrane potential of a photoreceptor is about 30 mv. This is much closer to zero than a typical neuron s resting membrane potential of 70 mv. The partial depolarization during darkness triggers continual release of neurotransmitter at the synaptic terminals. The neurotransmitter in rods, and perhaps in cones, is the amino acid glutamate (glutamic acid). At synapses between rods and some bipolar cells, glutamate is an inhibitory neurotransmitter: It triggers inhibitory postsynaptic potentials (IPSPs) that hyperpolarize the bipolar cells and prevent them from sending signals on to the ganglion cells. When light strikes the retina and cis-retinal undergoes isomerization, enzymes are activated that break down cgmp. As a result, some cgmp-gated Na_ channels close, Na_ inflow decreases, and the membrane potential becomes more negative, approaching 70 mv. This sequence of events produces a hyperpolarizing receptor potential that decreases the release of glutamate. Dim lights cause small and brief receptor potentials that partially turn off glutamate release; brighter lights elicit larger and longer receptor potentials that more completely shut down neurotransmitter release. Thus, light excites the bipolar cells that synapse with rods by turning off the release of an inhibitory neurotransmitter. The excited bipolar cells subsequently stimulate the ganglion cells to form action potentials in their axons. [13] Visual pathway: The axons of all retinal ganglion cells in one eye exit the eyeball at the optic disc and form the optic nerve on that side. At the optic chiasm, axons from the temporal half of each retina do not cross but continue directly to the lateral geniculate nucleus of the thalamus on the same side. In contrast, axons from the nasal half of each retina cross the optic chiasm and continue to the opposite thalamus. Each optic tract consists of crossed and uncrossed axons that project from the optic chiasm to the thalamus on one side. Axon collaterals (branches) of the retinal ganglion cells project to the midbrain, where they participate in neural circuits that govern constriction of the pupils in response to light and coordination of head and eye movements. Collaterals also extend to the suprachiasmatic nucleus of the hypothalamus, which establishes patterns of sleep and other activities that occur on a circadian or daily schedule in response to intervals of light and darkness. The axons of thalamic neurons form the optic radiations as they project from the thalamus to the primary visual area of the cortex on the same side. [14] AIMS & OBJECTIVES: To critically analyze the Alochaka Pitta MATERIALS & METHODS The Bruhat Trayi were scrutinised regarding the references for the Guna and Karma of the Alochaka Pitta. Later, physiologico-anatomical aspects of the eye with reference to sense of vision were studied from modern physiology books. Later, supportive correlation was done between Ayurvedic and modern views to build valid and reliable hypothesis regarding Alochaka Pitta in relation to the various anatomical and physiological aspects of the eye in relation to sense of vision. DISCUSSION There are five types of Pitta namely Pachaka, Ranjaka, Sadhaka, Alochaka, Brajaka. The Visesha Sthana of Alochaka Pitta is said to be Akshi. The main function of Alochaka Pitta is said to be Rupa Grahana i.e responsible for sense of vision. Photoreceptors are specialized cells that begin the process by which light rays are ultimately converted to nerve impulses. There are two types of photoreceptors: rods

5 907 and cones. Each retina has about 6 million cones and 120 million rods. Rods allow us to see in dim light, such as moonlight. Because rods do not provide color vision, in dim light we can see only black, white, and all shades of gray in between. Brighter lights stimulate cones, which produce color vision. In darkness, retinal has a bent shape, called cis-retinal, which fits snugly into the opsin portion of the photopigment. When cis-retinal absorbs a photon of light, it straightens out to a shape called trans-retinal. This cisto-trans conversion is called isomerization and is the first step in visual transduction. After retinal isomerizes, several unstable chemical intermediates form and disappear. These chemical changes lead to production of a receptor potential. In about a minute, trans-retinal completely separates from opsin. The final products look colorless, so this part of the cycle is termed bleaching of photopigment. An enzyme called retinal isomerase converts trans-retinal back to cis-retinal. The cis-retinal then can bind to opsin, reforming a functional photopigment. Cone photopigments regenerate much more quickly than the rhodopsin in rods and are less dependent on the pigmented layer. After complete bleaching, regeneration of half of the rhodopsin takes 5 minutes; half of the cone photopigments regenerate in only 90 seconds. Full regeneration of bleached rhodopsin takes 30 to 40 minutes. The absorption of light and isomerization of retinal initiates chemical changes in the photoreceptor outer segment that lead to production of a receptor potential. The neurotransmitter in rods, and perhaps in cones, is the amino acid glutamate (glutamic acid). Dim lights cause small and brief receptor potentials that partially turn off glutamate release; brighter lights elicit larger and longer receptor potentials that more completely shut down neurotransmitter release. Thus, light excites the bipolar cells that synapse with rods by turning off the release of an inhibitory neurotransmitter. The excited bipolar cells subsequently stimulate the ganglion cells to form action potentials in their axons. The functions of Alochaka Pitta can be related to the functions of photo-pigments, phyto chemicals and neurotransmitters which are responsible for the sense of vision. CONCLUSION There are five types of Pitta namely Pachaka, Ranjaka, Sadhaka, Alochaka, Brajaka. The Visesha Sthana of Alochaka Pitta is said to be Akshi. The main function of Alochaka Pitta is said to be Rupa Grahana i.e responsible for sense of vision. The functions of Alochaka Pitta can be related to the functions of photo-pigments, phyto chemicals and neurotransmitters which are responsible for the sense of vision. REFERENCES 1. Acharya JT. Charaka Samhita with p Acharya JT. Charaka Samhita with p Acharya JT. Charaka Samhita with p Acharya JT. Charaka Samhita with p Acharya JT, editor, Reprint ed. Susrutha Samhita with Nibandhasangraha commentary of Dalhana, sootrasthana; Dosha datu mala ksaya vridhi vignaniyam adhyayam: chapter 15, verse 3. Varanasi (India): Chaukambha Orientalia,2010; Acharya JT, editor, Reprint ed. Charaka Samhita with Ayurveda Dipika

6 commentary of Chakrapani Datta,sootrasthana; kuddaka chatuspadam adyayam:chapter 9, verse 4. Varanasi (India): Chaukambha Prakashan, 2007; Paradakara HSS, editor, 9 th ed. Ashtanga Hrudaya with Sarvangasundara commentary of Arunadatta and Ayurvedarasayana commentary of Hemadri.sootrasthana; dosadivignaniyam adhyayam:chapter 11,verse Varanasi (India): Chaukambha Orientalia; 2005; Paradakara HSS, editor, 9 th ed. Ashtanga Hrudaya with Sarvangasundara commentary of Arunadatta and Ayurvedarasayana commentary of Hemadri.sootrasthana; dosadivignaniyam adhyayam:chapter 11,verse 1-3. Varanasi (India): Chaukambha Orientalia; 2005; Paradakara HSS, editor, 9 th ed. Ashtanga Hrudaya with Sarvangasundara commentary of Arunadatta and Ayurvedarasayana commentary of Hemadri.sootrasthana; dosabediya vignaniyam adhyayam:chapter 12,verse 7-8. Varanasi (India): Chaukambha Orientalia; 2005; Toratora GJ, Derickson B. Principles of sons.inc; 2007, Toratora GJ, Derickson B. Principles of sons.inc; 2007, Toratora GJ, Derickson B. Principles of sons.inc; 2007, Toratora GJ, Derickson B. Principles of sons.inc; 2007, Toratora GJ, Derickson B. Principles of sons.inc;2007,617. Source of support: Nil Conflict of interest: None declared 908